Abstract:
A device suitable for use as an intra vaginal device or as a bolus where, after initiation, a member (usually a plunger) moves with a known movement characteristic and is involved in the stagger release of multiple materials. That moving member is used to time the discharge of one or more material from its reservoir in the device (there being separate powering of the timed discharge) or is used to both time and indirectly power the discharge of one or more material from its reservoir, such discharges preferably being in a staggered manner. Optionally the moving member as a plunger may itself also directly discharge a material from a reservoir.

Description:
This is a nationalization of PCT/NZ00/00155, filed Aug. 9, 2000, and published in English. 
   The present invention relates to dispensing apparatus for dispensing an agent or its precursor(s), methods of use thereof and related means, methods and applications. 
   There are many instances where it is desired to activate or allow the activation of the release of an active agent or its precursor(s) whether as a single dose, a continuous dose or as a pulsile dose. Instances include microprocessor control active delivery of agents as might be used to release a medicament into a body cavity such as, for example, disclosed in PCT/NZ98/00011. 
   Many forms of such active delivery device (in addition to microprocessor or other logic means capable of empowering the release) utilise a reservoir or barrel having a membrane or piston that separates the formulation of the active agent or its precursor(s) from a gas generating arrangement, eg, a hydrogel and its electrodes. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to providing the timing mechanism for dispensing apparatus (preferably which lends itself to an easier manufacturing procedure (as will be described hereinafter in more detail)). It is an object of the present invention to provide such apparatus and related means, methods and procedures. 
   The present invention has found there can be an effective staggering of materials to be delivered from a device (once initiated by some act) which thereafter is to continue with its delivery regime without a need for further human input where there is reliance on the movement (preferably rectilinearly) of a member or element having a known movement profile or characteristic as the stagger timing mechanism. 
   In one aspect the invention is a dispensing apparatus capable of expressing material, whether the same or different, from at least two reservoirs, the apparatus being characterised in that actuation means for expressing material from an outlet of a first of said reservoirs (hereafter “primary reservoir”) also directly or indirectly expresses or times the expression of material from the outlet(s) of at least one other said reservoir (hereafter “secondary reservoir(s)”) but only after a predetermined state of expression of the material from said primary reservoir has occurred. 
   Preferably said actuation means for expressing material from said primary reservoir includes a piston (hereafter “primary piston”). 
   Preferably said at least one said secondary reservoir at least in part includes a piston capable of expressing its material via its outlet. 
   In one embodiment said actuation means includes a gas generation unit the gas of which is capable of moving said primary piston. 
   Preferably said gas generation unit is a resistance circuit actuable to generate gas from the battery providing the powering therefor. 
   Preferably said gas generation unit includes a hydrogel electrolysed at least in part by a battery powered resistance circuit. In this respect see WO 94/01165, U.S. Pat. No. 5,460,242 and U.S. Pat. No. 5,741,275. 
   Preferably a switching mechanism is provided to allow the initiation of actuation of said gas generation unit. 
   In other embodiments said actuation means includes at least one of the group consisting of a spring, an osmotically expanding material, a chemical reaction, compressed gas, evolved or generated gas(es) and a motor. 
   Preferably said apparatus is capable of being inserted into a body cavity. 
   Preferably deployable members for retention in a target body cavity are provided. 
   Preferably said apparatus is of a configuration for a target mammal with retention features for intra vaginal use. See, for example, U.S. Pat. No. 4,091,807, WO 99/07346, WO 95/13760, WO 98/33452 and WO 96/29025. 
   Preferably at least one of the materials to be expressed is a liquid or liquid formulation. 
   Preferably at least one of the materials to be expressed is in the form of a solid or a solids formulation. 
   Preferably at least one of said outlets is sealed, plugged or otherwise closed yet is openable under the forces to act thereon as the associated material is pressed for expression out of such outlet(s). 
   Preferably at least one of said secondary reservoirs has its material expressible under the action of gas from said gas generation unit bypassing or ducting through said primary piston once the primary piston has moved a predetermined amount. 
   Preferably (at least) one of said secondary reservoirs has its material expressible under the action of said primary piston coming into contact with and driving a material expressing piston of a said secondary reservoir. 
   Preferably said primary piston carries a magnet capable of switch actuation for a circuit in turn, once actuated, to cause movement of means to express material from at least one said secondary reservoir. 
   Preferably said primary piston using a magnet/reed switch interaction can cause an expression of the material from at least one said secondary reservoir. 
   In another aspect the invention is as previously defined substantially as herein described with reference to any example thereof and/or any of the accompanying drawings. 
   In another aspect the invention is a dispensing apparatus comprising or including
         an assembly defining partitioned chambers where the partitioning member can be moved by gas pressure increase(s) in one chamber to reduce the volume of the other chamber,   a battery powered circuit actuable to generate gas within or for said one chamber,   at least one assembly defining at least one material containing reservoir with an outlet (sealed, plugged or otherwise optionally closed) it or each capable of being reduced in volume by a piston,   wherein at least one said piston of a said material containing reservoir is moved to express the associated material only once, under the action of said gas generation, said partitioning member has moved a predetermined amount.       

   Preferably said partitioned chambers have a piston as its partitioning member. 
   Preferably said one chamber of said partitioned chamber to reduce in volume has an outlet (sealed or otherwise) and contains a material expressible out of said chamber as said volume is reduced. 
   In another aspect the invention is a dispensing apparatus comprising or including
         an assembly defining partitioned chambers where the partitioning member can be moved to reduce the volume of the other chamber,   at least one assembly defining at least one material containing reservoir with an outlet (sealed, plugged or otherwise optionally closed) it or each capable of being reduced in volume by a piston,   wherein at least one said piston of a said material containing reservoir is moved to express the associated material only once said partitioning member has moved a predetermined amount.       

   Preferably said partitioning member is movable by mans of at least one of the group consisting of a spring, an osmotically expanding material, a chemical reaction, compressed gas, evolved or generated gas(es) and a motor. 
   Preferably a said piston of a said material containing reservoir is movable by means of at least one of the group consisting of a spring, an osmotically expanding material, a chemical reaction, compressed gas, evolved or generated gas(es) and a motor. 
   Preferably said partitioned chambers have a piston as its partitioning member. 
   Preferably said one chamber of said partitioned chamber to reduce in volume has an outlet (sealed or otherwise) and contains a material expressible out of said chamber as said volume is reduced. 
   In another aspect the invention is a multiple material dispensing apparatus having
         a primary reservoir containing a first material expressible via an outlet under the action of a primary piston, and   at least one secondary reservoir itself containing a material to be dispensed via an outlet under the action of a secondary piston, wherein said secondary piston is actuable directly by said primary piston after an at least partial expression of the material of the primary reservoir.       

   In still another aspect the invention is a dispensing apparatus capable of expressing materials, whether the same or different, from at least two reservoirs, the apparatus being characterised in that a piston (hereafter “primary piston”) in use will express or cause the expression at least some material from a reservoir and that piston, directly or indirectly, activates or causes the expression of at least some material from at least one other reservoir, the relative timing of the at least partial emptying of the reservoirs between or amongst the reservoirs being predetermined but nonetheless being dependent on said piston and its travel. 
   In still another aspect the invention is a dispensing apparatus capable of expressing material, whether the same or different, from at least two reservoirs in a delayed manner, the apparatus being characterised in that a member capable in use of moving or being set to move, can, upon predetermined movement occurring to provide the delay or delays, directly or indirectly express or time the expression of material from the outlet(s) of said at least two reservoirs. 
   Preferably each said reservoir includes a piston. 
   Preferably said member in use capable of moving, moves under the influence of at least one of the group consisting of a spring, an osmotically expanding material, a chemical reaction, compressed gas, evolved or generated gas(es) and a motor. 
   Preferably in use said delays are staggered. 
   Preferably said member capable in use of moving or being set to move is a piston capable of expressing material from its own reservoir. 
   Preferably said apparatus is in the form of a bolus or intra vaginal device, eg; for use as a bolus. 
   In another embodiment said apparatus is adapted for release of active ingredients into an environment. 
   In another aspect the invention consists in a dispensing apparatus capable of expressing materials, whether the same or different, from at least two reservoirs, the apparatus being characterised in that a piston in use that can be initiated to move or which, in its in use site, can move, will express or cause the expression of at least some material from a reservoir and that primary piston also, directly or indirectly, activates or causes the expression of at least some material from at least one other reservoir. 
   Preferably the expression of at least some material from at least one other reservoir is under the action of a piston in turn moved, initiated to move or allowed to move by the state of movement of the primary piston. 
   In another aspect the invention consists in a dispensing apparatus capable of expressing materials, whether the same or different, from at least two reservoirs, the apparatus being characterised in that a piston movable under the action of a generated gas in use will express or cause the expression at least some material from a reservoir and that primary piston also, directly or indirectly, activates or causes the expression of at least some material from at least one other reservoir. 
   In another aspect the invention consists in a device for intraruminal, intra vaginal, or the like body cavity use capable of expressing materials, whether the same or different, from at least two reservoirs, wherein the apparatus is characterised in that a piston in use will express at least some material from a reservoir and that piston directly or indirectly, activates or causes the expression of at least some material from at least one other reservoir. 
   In another aspect the invention is an intra vaginal device having
         (i) a progesterone containing material in a primary reservoir, and   (ii) oestradiol or an oestradiol containing material in a secondary reservoir, where, in use, a member which moves in a predetermined way provides a delay in the release of (ii) with respect to (i).       

   Preferably said device has four reservoirs to release in sequence, reliant on said member&#39;s movement
         (a) a progesterone containing material,   (b) oestradiol benzoate,   (c) cloprostenol sodium, and   (d) oestradiol 17β.       

   Preferably said device is also a device as previously defined. 
   In one embodiment said device is a bolus for use in a ruminant having in separate reservoirs a trace metal (eg; zinc) and an anthelmintic (eg; ivermectin) which is also a device as previously defined. 
   In another aspect the invention is, in a plural reservoir (solids and/or liquid) material dispensing apparatus, the use of a directly or indirectly (eg; through gas generation) driven member capable after initiation of progressive movement having predetermined travel characteristics as the initiator and/or force providing member for time staggered expression of material from the reservoirs. 
   In another aspect the invention is the use of a member initiable to move (directly or indirectly under battery power) in a predetermined progressive manner to act as the timing element in the expression from material from different reservoirs in at least a staggered manner. 
   Preferably, in acting as the timing element said member applies directly or indirectly force to an expression piston of at least one reservoir. 
   Preferably said member is itself an expression piston of a material containing reservoir. 
   In another aspect the invention is a method of, at least in part, serially or sequentially expressing materials from a delivery device, said method comprising actuating a battery powered device to move an element thereof in a substantially known manner to thereby, with delay of such travel, to act, staggered with respect to time, upon a material expression component of each material containing reservoir to thereby express such material via an outlet. 
   In still another aspect the invention is a method of stagger expressing materials from a delivery device, said method comprising setting, actuating or initiating the device to move an element thereof, firstly, to commence (directly or indirectly) materially expression from a first reservoir of the device, and secondly, after the element has traveled a predetermined distance and as it continues to travel, to commence (directly or indirectly) material expression from another material containing reservoir. 
   In another aspect the invention is a method of patterning the delivery of plural materials into a body cavity of an animal which comprises or includes the steps of
         introducing into a said cavity a device containing said plural materials,   discharging at least one of said plural materials from a reservoir under the action of a plunger which reduces the volume of a reservoir available therefor sometime after the initiation of the device, and,   by (direct or indirect) interaction with said plunger subsequently discharging at least one other material of the device from that material&#39;s reservoir within the device.       

   In one embodiment said device is an intra vaginal device. 
   In one embodiment said plunger is moved under the action of a gas generation unit. 
   Preferably said action with said plunger is by abutment with a piston to discharge said at least one other material. 
   Preferably said interaction with said plunger involves a bypass for a gas but moves said plunger to then in turn act directly upon a piston for discharging said at least one other material. 
   Preferably said interaction is indirect and involves magnetic switching. 
   Preferably said device is a bolus or an intra vaginal device and includes means of variable geometry deployable from an insertion condition to a retention condition. 
   Preferably said method is performed using, as said device, apparatus as previously defined. 
   In another aspect the present invention consists in a dispensing apparatus capable of expressing materials, whether the same or different, from at least two reservoirs, the apparatus being characterised in that a piston in use will express or cause the expression at least some material from a reservoir and that piston, directly or indirectly, activates or causes the expression of at least some material from at least one other reservoir, the relative timing of the at least partial emptying of the reservoirs between or amongst the reservoirs being predetermined but nonetheless being dependent on said piston and its travel. 
   Preferably the expressions are linked timewise to the travel of the piston. 
   Preferably the apparatus is for use as a bolus or as an intra vaginal device. Other uses could be for timed release of actives into any environment, eg; fishtanks, lubricants into bearings, etc. 
   Preferably the expressions are linked timewise to the travel of the piston. 
   Preferments in respect of the dispensing apparatus or the bolus of the present invention will now be described. 
   Preferably said apparatus is of a kind where the piston of said first reservoir advances without rotation. In other forms it may rotate. 
   Preferably the advancement of the piston of the first reservoir is under the action of a gas and/or an activated electrical circuit. 
   Preferably the material of at least the first reservoir is a fluid. Preferably that fluid is a liquid. Preferably the liquid is or contains an active ingredient (whether solid or not). In other forms the material may be a gas or a mixture of a gas and liquid. Any such liquids may include a solids content and/or itself is a mixture of multiple liquids. In some instances the material to be expressed from a reservoir can be a solid or almost a solid, eg loose powders, a gel, a capsule, or the like. 
   In some forms of the present invention at least one and preferably each of the reservoirs is provided with a closed outlet capable of being opened under the direct or indirect action on the contents of the associated reservoir, eg, as would be the case with, for example, a waxed or frangible seal. 
   Preferably said apparatus has the piston thereof movable under the action of a gas which is generated upon the device being switch activated, eg, at the time of insertion. 
   In some forms of the present invention the gas may be generated from a hydrogel or the like using an electrolysis dependent gas generation circuit capable of being activated. In still other forms preferably said gas is generated directly from the energisation of a circuit including a gas generation battery. 
   In some forms of the present invention the first reservoir may in turn discharge its content onto a down stream reservoir, eg utilising as a piston therebetween a seal between the materials for the purpose of discharging first material from the second reservoir. 
   In still other arrangements there is a direct discharge through a rupturable or dischargeable seal of the material of the first chamber and a sequential movement of the piston towards at least one other reservoir until such time as there is interaction therewith as a result of the pistons movement. Such interaction may be direct contact or penetration. For example, a needle type arrangement could penetrate the piston of the first reservoir to thus allow the action of a gas that moves the first piston directly onto a piston or like member of such a second reservoir. In the same or different apparatus such interaction might mean there might equally be some extension of the piston into the reservoir of another material to itself act as a separate delayed action thereof. 
   In still other interactions the piston may time (eg by magnetic interaction) some energisation of a release circuit forming part of a release arrangement of another reservoir. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention consists in the foregoing and also envisages constructions of which the following gives examples. 
     In the accompanying drawings 
       FIG. 1  shows a hybrid apparatus in accordance with the present invention where there can be an actuation of the device and some control of a discharge sequence of materials from different reservoirs in a pre-determined manner, 
       FIGS. 2A to 2D  shows a sequence of materials expression using a device substantially similar to that of  FIG. 1  with both a piston/needle and piston/piston interaction for the delayed deliveries, 
       FIGS. 3A to 3D  in a similar manner to that of  FIGS. 2A to 2D  shows an expression sequence again with a device similar to that of  FIG. 1  but this time with a primary piston interacting directly on a piston of at least two of the secondary reservoirs with stagger timing as to delivery therefrom, 
       FIG. 4  shows the rate of vehicle delivery for a device of a kind as shown in  FIG. 1  in a simplified form, 
       FIG. 5  shows the effect of the needle and piston (diamond) or piston only (square) on delivery rate at 38° C. of vehicle from an infusion reservoir of a device possessing the bolus reservoir option as depicted in the embodiments shown in  FIGS. 2A to 2D , 
       FIG. 6  shows the effect of short secondary piston (circle) or long secondary piston (square) upon flow rate at 38° C. of vehicle from the infusion reservoir of a device possessing piston/piston interaction options as shown in options of  FIGS. 2A to 2D  and more particularly  3 A to  3 D, 
       FIG. 7  shows a plot to show the effect of the static resistance of the piston and seals of a primary bolus reservoir and the subsequent influence thereof on time lag between initiation of hydrogen production of a gas cell and release of a secondary reservoir material and vehicle from the primary reservoir,  FIG. 7  showing the release of fluorescence from a secondary reservoir with a high static pressure piston, 
       FIG. 8  is a similar plot to that of  FIG. 7  but in respect of a low static pressure piston, 
       FIG. 9  shows the use of an interaction with the piston to time subsequent discharges, 
       FIGS. 10A through 10D  show a device having (shown diagrammatically and not in an assembly) a sequence of three secondary reservoirs capable of being activated by passage past, for example, a read switch of a magnet that moves as the moveable element or member, and 
       FIG. 11  shows a most preferred form of the present invention having materials discharged from the primary reservoir under the action of a primary piston (moved by gas being generated after initiation), the primary piston subsequently, by abutment on piston extensions of two secondary reservoirs, leading to the staggered discharge from the secondary reservoirs. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   While the preferred propulsion mechanism for the primary piston is a gas generating or hydrogel cell, other mechanisms may be used. 
   Other mechanisms that may be employed to drive the primary piston (or secondary pistons, especially following activations by a primary piston via a magnet and reed switch) include;
         a spring,   an osmotically expanding material, e.g. gelatin,   chemical reaction, e.g. acid/base reaction resulting in the liberation of CO2,   compressed gas, e.g. a hydrocarbon, and   a motor, e.g. a “watch” or turning screw.       

     FIG. 1  shows a main barrel or reservoir having an outlet the upper end adjacent to smaller reservoirs. Preferably the formulations are protected within the barrel and smaller reservoirs by rupturible seals  1 . A primary piston  2  acts to dispense the material from a primary reservoir  3  as a result of an increase in pressure from a gas cell  4  that is activated by a switch  5 . The material of the primary reservoir acts upon a secondary piston  6  of a secondary reservoir  7  to dispense the secondary reservoir material after the rupture of the secondary reservoir seal. The primary piston may also act directly upon a second secondary piston  8  to dispense the contents of a second secondary reservoir  9 . The primary piston may also be pierced by a needle  10  thereby enabling gas to by-pass the primary piston and act upon a third secondary piston  110  which in turn dispenses the contents of reservoir  11 . Also present on the device are means by way of retention arms  12  for locating the device in a body cavity such as a vagina. 
   One configuration of the  FIG. 1  option is better presented in  FIGS. 2A to 2D . As the primary piston commences its migration towards the secondary reservoir, a dosage material (e.g. tablet) located within the secondary reservoir is expelled. Towards the end of the primary pistons migration it acts upon a second secondary piston whilst simultaneously being pierced by a needle. This action has two results;
         (1) a dosage material in the second secondary reservoir is expelled, and   (2) hydrogen from the gas cell is able to bypass the primary piston in order to act upon the third secondary piston of the third secondary reservoir and, once sufficient pressure has been reached, expel the contents of said third secondary reservoir.       

   A different configuration is presented in  FIGS. 3A to 3D . As the primary piston commences its migration towards the secondary reservoir a dosage material (e.g. tablet) located within the secondary reservoir is expelled. Towards the end of the primary pistons migration it acts upon a second secondary piston and thereby a dosage material in the second secondary reservoir is expelled. Following this action the primary piston commences action upon a third secondary piston and thereby a dosage material in the third secondary reservoir is expelled. 
     FIG. 4  shows the rate of vehicle delivery from a device similar to that represented in  FIG. 1  with the exception that the needle  10  and piston  11  are absent. 
   The action of the primary piston coming into contact with a secondary piston reduces the flow of vehicle from the infusion reservoir ( FIG. 5 ). However no additional reduction in flow of vehicle from the primary reservoir is observed as a result of the action of the primary piston coming into contact with the needle as present in said third secondary reservoir mechanism of  FIGS. 2A to 2D  (see  FIG. 5 ). 
   In  FIG. 5  the arrow represents the time point at which the primary piston comes into contact with the second secondary piston and/or needle. The vehicle was aqueous 2% HPMC held at 38° C. The interaction between the needle and piston as shown by the diamonds and the interaction between the piston with a piston is shown with the squares. 
   The action of the primary piston coming into contact with a second secondary piston reduces the flow of vehicle from the primary reservoir ( FIG. 6 ). However selection of long (i.e. projecting further into the primary reservoir) or short pistons for the second secondary reservoir piston and altering the external resistor allows for control of the flow rate from the primary reservoir ( FIG. 6 ). 
   In  FIG. 6  the vehicle is aqueous 4% HPMC at 38° C. and the circles depict the effect of a short piston whilst the square depict the effect of a long piston. The piston options are those depicted as piston to piston interactions in  FIGS. 2A to 2D  and  3 A to  3 D. 
   The static resistance of the piston and seals of the secondary reservoir influences the time lag between initiation of hydrogen production by the gas cell and release of the secondary reservoir dosage material and vehicle from the primary reservoir (see  FIGS. 7 and 8  and Table 1). 
   Table 1. Effect of high static pressure (2 points of contact between piston and reservoir walls) and low static pressure (1 point of contact between piston and reservoir walls) upon the lag between initiating hydrogen production by the gas cell and release of a dosage unit from the secondary reservoir. 
   
     
       
             
             
             
           
         
             
                 
             
             
               Replicate 
               High friction 
               Low friction 
             
             
                 
             
           
           
             
               1 
               655–660 mins 
               125 mins 
             
             
               2 
               Did not release 
               410 mins 
             
             
                 
             
           
        
       
     
   
   Choice of appropriate rod lengths for the second secondary delivery mechanism and static pressure of the pistons within each individual reservoir would enable the selection of any desired delivery rate and profile. 
     FIG. 7  shows the release of fluorescence from the secondary reservoir with a high static pressure piston whilst  FIG. 8  shows the release of fluorescence from the secondary reservoir with a low static pressure piston. 
     FIG. 9  shows a main barrel or reservoir  1  in which a piston  2  containing a magnetic material  3  is enabled to migrate within the main barrel as a result of an increase in pressure from a gas cell  4 . The magnet material is able to activate individual sensors  5  or sensor part or an array  6  which in turn control the action of a device(s)  7  and/or  8 . 
   In Vivo Performance of Multiple Material Dispensing Option of  FIGS. 3A to 3D   
   An in vivo trial investigated the performance of the bolus reservoir mechanism of  FIGS. 3A to 3D . Devices were assembled as per  FIGS. 3A to 3D , and inserted into the vagina of normal cattle for 9 days. It was visually confirmed upon removal of the devices that all chambers were activated and the dosage units therein delivered. 
   Description of Multiple Material Dispensing Option of  FIGS. 10A to 10D   
   The configuration of this option is presented in  FIGS. 10A to 10D . As the primary piston commences its migration towards the second reservoir dosage material (e.g. tablet) located within said secondary reservoir are expelled due to the action of a magnet within the primary piston activating sequential reed switches thereby initiating the electrolytic production of gasses. 
   In Vitro Performance of Multiple Material Dispensing Option of  FIGS. 10A to 10D   
   Three devices as per  FIGS. 10A to 10D  and  FIG. 9  were constructed. Activation and expulsion of dosage units from all bolus reservoirs was visually confirmed. 
   In Vivo Performance of Multiple Material Dispensing Option of  FIGS. 10A to 10D   
   An in vivo trial investigated the performance of bolus reservoir mechanism of  FIGS. 10A to 10D . Devices were inserted into the vagina of normal cattle for 9 days. It was visually confirmed upon removal of the devices that all chambers had been activated and the dosage units therein delivered. 
   Preferred Multiple Material Dispensing Option 
   A preferred configuration is detailed in  FIG. 11  and Table 2. It consists of a cylinder that is divided by a primary piston  13  in a primary reservoir  14 , containing the formulation, and part  15 , containing the gas and the gas producing components. The action of primary piston  13  upon the formulation contained in the primary reservoir  14  causes the secondary piston  16  to expel the material of the secondary reservoir  17  following the rupture of the secondary reservoir seal  18 . 
   Following the expulsion of formulation primary piston  13  migrates towards the outlet of secondary reservoir  17  thereby coming into contact with rod  19 . Rod  19  of the second secondary piston  20  acting under the influence of the primary piston  13  drives the second secondary piston  20  to expel the material of the second secondary reservoir  21  following the rupture of the second secondary seal  22 . 
   Following further expulsion of formulation the primary piston  13  migrates further towards the outlet of the third secondary reservoir  17  thereby coming into contact with rod  23  of the third secondary piston  24 . Rod  23  acting under the influence of the primary piston  13  drives the third secondary piston  24  to expel the contents of the third secondary reservoir  25  following the rupture of the third secondary reservoir seal  26 . 
   
     
       
             
           
             
             
             
           
             
             
             
           
         
             
               TABLE 2 
             
           
           
             
                 
             
             
               Physical parameters of design brief for electronically modulated 
             
             
               intravaginal synchrony device. 
             
           
        
         
             
                 
               Parameter 
               Specification 
             
             
                 
                 
             
           
        
         
             
                 
               Gross physical dimensions 
                 
             
             
                 
               Delivery component outer diameter (cm) 
               2.5 
             
             
                 
               Delivery component length (cm) 
               13 
             
             
                 
               retention mechanism width (cm) 
               15 
             
             
                 
               Primary reservoir (1) 
             
             
                 
               Volume (ml) 
               30 
             
             
                 
               Delivery rate (ml/day) 
               3.33 
             
             
                 
               Secondary reservoir (5) 
             
             
                 
               rod protrusion into primary 
               NA 
             
             
                 
               reservoir (%) 
             
             
                 
               Volume (ml) 
               0.10 
             
             
                 
               Second Secondary reservoir (8) 
             
             
                 
               rod protrusion into primary 
               11 
             
             
                 
               reservoir (%) 
             
             
                 
               Volume (ml) 
               0.10 
             
             
                 
               Third secondary reservoir (11) 
             
             
                 
               rod protrusion into primary 
               1 
             
             
                 
               reservoir (%) 
             
             
                 
               Volume (ml) 
               0.10 
             
             
                 
                 
             
           
        
       
     
   
   EXAMPLE 1 
   Reservoir Contents for Intra Vaginal Product 
   Primary reservoir material: 
   
       
       
         
           15 mg/ml progesterone dissolved in ethanol thickened with 4% hydroypropyl methyl cellulose (P4)
 
Secondary reservoir material:
 
           a tablet, liquid or semi-solid dosage unit of 10 mg oestradiol benzoate (ODB)
 
Second secondary reservoir material:
 
           a tablet, liquid or semi-solid dosage unit of 1000 mcg of cloprostenol sodium (PG)
 
Third secondary reservoir material:
 
           a tablet, liquid or semi-solid dosage unit of 7.2 mg oestradiol 17beta (E17b) 
         
       
     
  
   EXAMPLE 2 
   Contents of Intraruminal Product 
   
       
       
         
           Primary reservoir contents—Zinc oxide liquid or semi-solid formulation 
           Secondary reservoir(s)—tablet, liquid or semi-solid Ivermectin 60 mg