Abstract:
An infusor unit for dispensing a medicament by injection including a vial having an open end and a closed end and a resilient piston adapted to be initially partially inserted into said vial. The piston having a central through bore which is sealed by a transverse diaphragm and a chamber formed at one end of the piston by the diaphragm and a reduced entryway at its open end to define internal shoulder means. A substantially rigid hollow tubular infusor means which includes means for securing a sharpened cannula which extends outwardly from one end and in communication with the transparent interior of said infusor. The opposite end of the infusor having hollow means for sealing engagement with the piston bore for pre-assembly and, subsequently, to cooperatively penetrate said diaphragm to provide access of the hollow infusor and its connected passageway with the cannula to the interior of the piston sealed vial.

Description:
BACKGROUND OF THE INVENTION 
     In present day medical sciences, there is a distinct trend toward the unit-dose systems wherein a pre-determined quantity of drugs can be pre-packaged and stored for extended periods of time and usable on quick notice for emergency situations which may arise in the clinic or the operating room. Heretofore, conventional syringes have been utilized to aspirate the medicament from a closed vial by puncturing a diaphragm across the vial with the cannula, aspirating the syringe, and thereby filling the syringe for usage. This procedure is quite time consuming and, additionally, has the disadvantage of drugs being aspirated from a vial and the drug replaced by water or a similar liquid substance. 
     Several unit-dose devices have been available on the market but have had several distinct disadvantages. One such device requires an expensive holder to which a sterilized cannula must be attached and, due to the expense of the holder, is often not readily available at the time of need, the expense precluding the availability of additional holders. Additionally, such devices do not have means for pre-assembly in a non-activated condition and their more common activation movement requires at least a turn of some rotational degree and, more commonly, a combination of insertion, seal break-off, and a twisting motion which is relatively complex to the uninitiated user. Additionally, none of the existing devices provides aseptic protection over all drug container and drug contact surfaces to the moment of infusion. At best, such devices provide minimal drug contact surfaces which, up to the moment of aspiration for a show of blood when a venipuncture is necessary, are not exposed to the drug, but which immediately upon aspiration pull their plunger or plug back across vial surfaces which have been exposed to the air and which consequently can subject the infused drugs to aerobic contamination. 
     Probably one of the most important deficiencies of such existing prior art is that none of these devices provides a visual observation of aspirated blood without introducing the blood to the drug container. 
     Lastly, because of the typically rotational activation nature of such existing syringe devices, these devices are necessarily round  pg,3 tubular members or generally cylindrical in shape, thereby requiring cylindrical embodiments in co-acting holder, activators and similarly related components of such devices. 
     Prior art devices having the limitations enumerated above can be found in the United States Pats. issued to R. W. Ogle, such as Nos. 3,303,846; 3,330,280; 3,376,866; 3,378,008; and the patent to Fred M. Killinger, no. 3,841,329. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide a simple, convenient to use, parenteral drug containing device that can be stored for long periods of time and, at the moment of need, easily and quickly readied for use with a single linear movement. 
     Another object of this invention is to provide a device which is capable of giving a readily observable indication that a venipuncture has been made by a show of aspirated blood within the device that does not necessitate drawing the blood back into the drug containing vial. 
     Further, in the interest of maintaining good prevention of contamination, it is an object of this invention to preclude contact from the surrounding air of any drug container surface which will be at any time in contact with the drug. 
     An additional object to the invention is to provide an infusor unit which, once a venipuncture or needle entry is made, permits the injection of several vials of the same or varying drug content by having the ability to disengage the vial without or with minimum aspiration of blood or body fluid into the removed vial. 
     Aspirating in a unit-dose system should occur only at desired times. This is accomplished in the present invention by keeping the retentive force of the piston or plug to the vial wall at a control level. By controlling the drag on the vial wall and retention of the infusor unit probe to the plug, a low level of aspirating pull can be exerted against the plug without disengagement. An abruptly higher pull disengages the probe from the plug leaving it in the vial without aspiration. The plug, with the probe removed, reseals the vial or simply remains at the bottom of the empty vial ready for discard. Meanwhile, the infusor unit, with the cannula still implanted in the venipuncture, is ready to receive and engage a fresh vial. In this way, several drugs or vial quantities can be injected with a single venipuncture. A secondary advantage of the disengagement of the probe from the plug or piston is its non-reuse. If the plug were designed to aspirate easily it would encourage use of aspirating drugs from a bulk container. Making aspiration difficult encourages single use and disposal with its inherent sterile advantages. Since the device is intended and designed for single usage the disengagement of the plug from the probe defeats mis-use, re-use, making the package more security conscious and substantially tamper-proof. 
     All of the afore-mentioned objectives can be shown in the detailed description which follows. These objectives, together with the simple, economical manufacture, can be readily achieved by this invention in a manner superior to those of any existing devices used for a similar function. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a preferred embodiment of the present invention in its assembled relationship; 
     FIG. 2 is an exploded view of the various elements of the preferred embodiment; 
     FIG. 3 is a side elevational view in partial section of the device shown in FIG. 2 in assembled relationship; 
     FIG. 4 is an end view of the infusor unit shown in FIGS. 1 through 3; 
     FIG. 5 is an expanded elevational view in partial section of the probe of the infusor unit; 
     FIG. 6 is an elevational view in partial section of the probe, piston and vial in pre-assembled relation; 
     FIG. 7 is an elevational view in partial section showing the probe as it makes its initial penetration of the diaphragm in the piston bore; 
     FIG. 8 is an elevational view in partial section showing the probe in its final seated position at the beginning of the evacuation of material from the vial; 
     FIG. 9 is an exploded view of the elements making up a second embodiment of the infusor unit; 
     FIG. 10 is an elevational view in partial section showing the pre-assembly of the probe with the piston of said second embodiment; 
     FIG. 11 is an elevational view in partial section showing the probe of the second embodiment in final seated position; 
     FIG. 12 is an elevational view in partial section of a third embodiment of the present invention; 
     FIG. 13 is an end view of the third embodiment as taken along Line 13--13 of FIG. 12; 
     FIG. 14 is an elevational view in partial section of an alternate design for the probe; 
     FIGS. 15 and 16 are variations on the interior bore chamber of the piston used with the present invention; 
     FIG. 17 is an elevational view in partial section of a device using the teachings of this present invention for the purpose of having two vials for storage of liquid and dry materials which cannot be pre-mixed until immediately before injection; 
     FIG. 18 is an elevational view in partial section of the device shown in FIG. 17 when the materials have been mixed; 
     FIG. 19 is a plan view in partial section of a filtration device for use with the present invention; and 
     FIG. 20 is a side view in partial section of the device shown in FIG. 19. 
    
    
     DETAILED DESCRIPTION 
     A linear activated medicament infusor unit 10, of the type contemplated by the present invention, includes a tubular container 12 open at one end, a resilient plug or piston 14, and a substantially rigid hollow tubular infusor means 16 carried by a frame having a sharpened cannula 18 suitably supported and in communication with one end of the tubular infusor means 16. 
     Referring now to FIGS. 1 through 5, the infusor 16 includes a framework having a base 20 and a pair of sidewalls 22 symetrically placed on either side of the axis of the frame. In this instance, the sidewalls 22 are reinforced by ribbing 24 which can be eliminated in smaller model designs. The upper or opposite end of the sidewalls 22 are joined by a yoke 26 having a central aperture 28 for acceptance of the vial 12 and a pair of laterally extending flanges or wings 30 for grasping by the index and middle finger of the operator. In this embodiment the reinforcing ribs 24 are curved at their upper extremity for accommodation of the operator&#39;s fingers. 
     In the present embodiment, the cannula 18 is insert-molded centrally of the base 20 and gripped at spaced points 32 and 34, the latter being accomplished by use of spaced walls 36 which re-enter and join at point 34. This technique permits the grasping of the cannula 18 to more positively locate it during the injection molding of the infusor. The bridge formed by walls 36 and re-entrant portion 34 carry a transparent tubular member 38 having a hollow interior bore 39 larger in diameter than the cannula 18 and in communication therewith. This forms a transparent chamber which will be discussed hereinafter. At the upper end of tubular member 38 is a probe or spike 40 which can be best seen in FIG. 5. The probe 40 in this embodiment includes a frustoconical portion 42 having a pre-determined major and minor diameter which is spaced a short distance from the end of the tubular member 38. The end is tapered to provide a sharp point 44 with a large opening to the interior bore 39 of tubular member 38. Intermediate the tip 44 and the frustoconical portion 42 is an annular enlargement 46 for purposes best set forth hereinafter. Spaced axially from the cone 42 is a tapered annular flange 48 whose function will be described hereinafter. It should be noted that the distance between the major diameter or frustoconical portion 42 and the flange 48 is controlled. Thus, the major diameter of the frustoconical portion 42 forms a shoulder 50 in opposition to the flange 48, for purposes best set forth hereinafter. 
     The vial 12 is a tubular member which is shown to be cylindrical in this embodiment but could be square, elliptical, or any other suitable cross sectional configuration. The vial is open at one end 60 and includes a necked in portion formed by a rib 62 having a pre-determined axial extent and an external groove 64. In this embodiment the rib 62 has a wall thickness substantially equal to the balance of the vial but could be replaced by other suitable spaced protuberance means to form the necked in portion. 
     The plug or piston 14 is a resilient elastomeric member including a body 70 having a plurality of rings equal to or slightly larger than the internal measurement of the vial 12 and complementary to its cross-sectional shape, in this instance, cylindrical. The rings are axially spaced and in the present embodiment there is a first ring 72 adjacent the outer end of the piston 14; a second ring 74 intermediate the extremities of the piston and spaced from the first ring 72 a distance substantially equal to the axial extent of rib 62; and a third ring 76 at the inner or opposite end. The inner end face 78 is generally concave and leads in its center portion to the bore 80. The bore 80 is sealed by a transverse diaphragm 82 and has a tapered entryway 84 at the outer end and an inwardly directed annular rib 86 which restricts the bore 80 and provides a pair of oppositely directed shoulders 88 and 90. The inside shoulder 88 and the diaphragm 82 serve to form a chamber 92 which is generally frustoconical in cross section and equal to or slightly larger in volume than the frustoconical portion 42 of the probe, for purposes best set forth hereinafter. Further, it will be noted that the rib 86 has an internal transverse measurement equal to or less than the minor diameter of the frustoconical portion 42. 
     Referring now to FIGS. 6 through 8, the piston 14 is assembled with the vial 12 with the first and second ring 72 and 74 disposed on opposite sides of the rib 62. The probe 40 is introduced into the tapered entryway 84 and through the aperture formed by rib 86 resulting in a lateral compression of the resilient rib 86 until such time as the annular rib or ring 46 enters the chamber 92 and rests on the shoulder 88. The axial disposition of the various parts on the probe, including point 44, is such that the bevelled point 44 will distort the diaphragm 82 and the frustoconical portion 42 will cause the piston 14 to bulge sideways into intimate engagement by increase of the surface area of rib 72 and the intermediate portion of the body 70 in contact with the rib 62 and its outwardly-facing shoulder 63. In this fashion the probe can be pre-assembled with the closed vial for storage prior to usage, as will be set forth hereinafter. To assist in maintaining the telescopic relationship between the probe, vial, piston and the general framework, the ring-like yoke 26 is provided with a pair of depending resilient members or fingers 100, as best seen in FIGS. 2 and 3. These fingers 100 will engage in the grooves 64 and prevent inadvertent disassembly from this pre-assembled position. 
     Further axial thrust of the probe 40 into the bore 80 of the piston 14 causes greater outward forces to be applied to the elastomeric piston so that it distorts and frictionally engages the sidewall of the vial 12, and more particularly, insures engagement between the annular rib 62 and the body 70 of the piston. This relative axial movement between the piston and the probe results in a rupturing of the diaphragm 82 with the frustoconical portion 42 moving axially, as seen in FIG. 7, until its larger lower end, and particularly its shoulder 50, clears the internal shoulder 88 against which it seats. The flange 48 is then positioned against the outer shoulder 90 and due to the volume of the chamber 92, a major amount of the lateral forces incurred in the telescoping operation are removed and the piston 14 reverts to substantially its initial shape. The locking action incurred by the introduction of the probe 40 is primarily due to the side pressure against the vial by the frustoconical configuration of part 42 and its associated flange 48 which keeps the piston stationary with respect to the vial while the probe is being advanced through the piston. It is this combination of drag, or holding power, between the piston and vial, as well as a partial hydraulic lock, which holds the piston while the diaphragm is being punctured. It is preferable to employ this mechanical lock or drag rather than relying totally on hydraulic locking since the latter increases pressure to the drug causing squirting when the tip pierces the diaphragm. Thus, a combined balanced use of these forces will provide the best detent and differential action for initial engagement of the probe and subsequent puncture of the piston by a simple, straightforward linear motion. It will be appreciated that when the probe 40 is in the pre-assembled position, as seen in FIGS. 1, 3 and 6, all of the contact surfaces of the vial and the bore 80 of the piston are closed or covered in such a fashion that it is possible to maintain aseptic conditions at that end of the infusor prior to injection of the medicament. Additional axial force on the vial 12, after puncture as seen in FIG. 8, results in an evacuation of the contents in vial 12 through the interior of the probe 30, the hollow transparent tubular portion 38, and thence through the cannula 18 into the patient, either by venipuncture or through intramuscular injection. 
     As best seen in FIGS. 2 and 3, the cannula is protected by a cover 110 which can, if desired, be integrally molded to the needle and provided with a fracture point 112 at its juncture to the frame and, at the opposite end, as illustrated, can be closed by crimping, by suitable means such as heat or ultrasonics, to provide a flat portion 114 to seal off the free or sharpened end of the cannula for the function of maintaining aseptic conditions as well as protecting the sharpness of the ground end. 
     In the use of this embodiment of the invention the entire assembly can be shipped with the vial pre-assembled to the probe or, alternatively, can be packaged separately. In either event, the nurse or doctor can preassemble, if it has not already been so done, by inserting the vial into the cylindrical yoke 26 and by a simple axial pressure, seat the probe in the position shown in FIG. 6. Further axial force on the closed end of the vial 12 will puncture the diaphragm 82, as seen in FIG. 7, until the probe is seated in the chamber 92. With the plug being distorted laterally until the probe is seated, the present design permits the point to continue penetration well beyond the minimum puncture to insure establishment of clear fluid flow. The chamber 92 also gives rise to a sudden drop in penetration force, creating a good detent feel for tactile feedback that the puncture has been made. If it is found necessary to use the drug, the operator will grasp the flattened portion 114 of the needle cover 110, fracture the juncture 112 by twisting, and axially remove the cover 110 to provide a sterilized cannula that is only momentarily exposed to aerobic conditions. Additionally, by carrying out the puncture of the diaphragm before breakage of the needle seal it is possible to eliminate any possibility of hydraulic discharge caused by pressures developed during penetration of the spike into the piston. Thus, for the nurses setting up medicaments, particularly for use in the operating room, this product, with its minimum number of parts, is capable of being activated for use with only one motion, namely, jamming the vial into the probe penetrating point. No &#34;coupling up&#34; is necessary nor are there any magical rotational forces required to insure proper usage. In the event a venipuncture is performed, after air has been cleared from the tubular portion 38 and the cannula 18, aspiration, by slow withdrawal of the vial 12 will reveal that a good venipuncture has been made since the blood can be seen in the transparent tubular portion 38 without introduction of such blood into the vial 12. This is particularly important where the medicament in the vial 12 may be viscous in nature. 
     It will be recognized by those skilled in the art that the clear tubular portion 38 could be extended to the base 20 and its central portion 32 and communication provided through a Leur fitting 166 and the inserted molded cannula 18 not provided. An independent cannula having a female Leur fitting (not shown) could then be utilized should this be found desirable. The function of the device would remain substantially identical. 
     In the first embodiment the plug 14 was provided with three substantially identical annular ring members 72-76 which cooperated with the rib 62 for maintenance of the plug 14 relative to the vial 12 during introduction of the probe 40. Referring now to FIGS. 9 through 11, it can be seen that a similar plug 14a can be used with a vial 12a having a generally smooth interior wall that does not have an internal rib, as was found in the first embodiment. The disposition of the entry 84a, the rib 86a, the chamber 92a, and the diaphragm 82a, are substantially identical to the first embodiment. The major difference in this embodiment is the disposition and axial extent of the annular rings 120, 122 and 124. The ring 122 is positioned immediately adjacent to the first ring 120 and is separated therefrom by a minimal groove 121. When the piston 14a is introduced into vial 12a, a ring 120, having a slightly larger diameter than ring 122, is positioned atop the outermost open end of vial 12a, as best seen in FIG. 10. The introduction of the probe 40a causes a lateral swelling until the ring 120 sits in overlying relationship. Until such time as the frustoconical portion 42a is positioned within the chamber 92a, the piston, due to its excessive drag and the overriding ring 120 is substantially locked relative to the sidewall of the vial 12a, thereby permitting puncture of the diaphragm 82a by the tip 44a. Operation of this device is substantially identical to the first embodiment. 
     Each of the two previous embodiments have been described as having imperforate diaphragms 82 and 82a. Under certain circumstances, it can be desirable to have a diaphragm 130, as seen in FIGS. 12 and 13, which is pre-slit. Thus, the point 44b in this embodiment is not cut on the bias but rather is slightly tapered and provided with a blunt nose 132 for opening the slit diaphragm when the probe 40b is moved axially relative to the piston 14b to seat the frustoconical portion 42b within the chamber 92b. The operation for pre-assembly, injection, etc., is substantially identical to the previous two embodiments. 
     While the factor of aspiration by movement of the vial has been previously discussed in a general manner, it should be recognized that aspiration is possible, but also can be controlled. It has been found that where the sidewalls of the entryway 84 substantially support the rib 86 there is a very short moment arm and hence the rib is rigidified and aspiration is possible. For example, if the entryway 84, as seen in FIG. 15 and the previous embodiments, is frustoconical in section with the narrower portion adjacent the rib 86, there is little tendency for the rib to move downwardly, as viewed in the drawing. If, however, the entryway is counterbored, as shown at 140 in FIG. 16, it can be seen that there is a greater degree of space for the rib to move into, either by flexing or crushing, when a retrograde movement is applied to the probe. Such a configuration would prevent aspiration to a substantial degree since the probe would readily disengage, with its shoulder 50, not shown, coming disengaged from shoulder 88c by flexure of the rib 86c downwardly into the counterbore 140. This would be an ideal configuration for those instances where aspiration would have a negative value and where quick removal of the vial for replacement by a second vial would be desired. It has been found that when the configuration shown in FIG. 15 and the previous embodiments have been used, the shallow undercut beneath the corner of rib 86 will not release the prove during aspiration unless a high force rapidly applied will cause this rib 86 to bend downwardly and compress outwardly, as by beam loading, to bend the short arm out of the way. Thus, aspiration is possible when the vial is withdrawn slowly but will result in removal of the piston from the probe if a quick force is applied in a retrograde direction to the vial. 
     On the other hand, it is conceivable that there are instances where it would be desirable to provide aspiration in a positive fashion. To this end, the probe can be varied by undercutting two sides of the frustoconical section 42d as seen in FIG. 14, to provide a pair of resilient arms 140 that will flex during insertion and seat against the shoulder 88 in a positive fashion which will substantially prevent removal from the chamber 92. 
     For certain types of drugs such as pentothal, which have short post-mixture life, crystals can be packaged for subsequent hydration into administerable form. In FIGS. 17 and 18 the vial 12e is substantially identical to the embodiment shown in FIGS. 9 through 11 with a piston 14e of similar configuration. This vial would be filled with a liquid solution, such as water, and preferably would be a glass vial. A second vial 150 has its lower end in communication with a probe 152 having a configuration substantially identical to the probe used in the embodiments shown in FIGS. 1 through 11. The vial 150 has a diameter equal to or less than the internal diameter of vial 12e and would generally contain and be manufactured from a material compatible with the dry crystals of the drug which must be hydrated. To accomplish hydration, the probe 152 is forced through into pierced relationship with the piston 14e in vial 12e. Axial telescoping of vial 150 into vial 12e results in the introduction of the liquid in vial 12e into vial 150, in a manner shown in FIG. 18. As will be appreciated by those skilled in the art, the two vials would initially be activated in the position shown in FIGS. 17 and 18. When the liquid is transferred from vial 12e to vial 150 there is a tendency for the air in the free space of the two vials to become compressed and tend to force the two vials apart when operator-applied force is removed. Thus, the operator preferably should hold the two vials in the position of FIG. 18; insert the pre-mixed assembly into an infusor; penetrate the diaphragm of piston 14e in vial 150; invert the infusor and carefully bleed off the air while holding the second vial immobile relative to the first vial to thereby prevent expulsion of the drug prior to injection in the patient. To overcome such manipulative action by the operator it would be possible to provide a rotatable or snap action locking collar, not shown, to maintain the vials in the position shown in FIG. 18. 
     It is also contemplated that the piggy-back pre-assembly of FIG. 17 could be packaged in an attractive tubular cover, not shown, that would lock the two vials in this position, provide a tamperproof cover and yet permit axial collapse for telescoping the vials for mixing before exposure to atmospheric conditions. The piggyback telescoped vials would then be inserted into an infusor unit and the hydrated medicament could then be injected into the patient in the fashion described hereinbefore. 
     In order to insure that foreign matter which might be inadvertently found in a medicament or a crystal from a hydrated medicament, not be introduced into the patient&#39;s blood vein, a filter device can be introduced into the construction of the present invention. Referring now to FIGS. 19 and 20, the contemplated filter includes a strip of porous filter material which is bent back upon itself to cover the end of the cannula 118 at the point it leaves the yoke 34 and enters the hollow tubular portion 38. The filter 160 would be bound along its free open edges 162 by the plastic materials forming the tubular portion 38 and the bridge 34, thereby forming an envelope which encloses the free end of cannula 118. This can be accomplished at the time of insert molding the needle into the framework of the infusor unit. 
     From a manufacturing standpoint, it will be appreciated that the fabrication of the infusor unit with its framework, insert molded cannula and cover, can be accomplished on standard injection molding equipment. The cannula is adequately held intermediate its length so that damage is not done to the ground point. The cover can be simultaneously molded and sealed at a secondary operation. This eliminates subsequent processing, such as glueing or assembly of the needle to the end of a framework, and, assuming that the parts are &#34;clean&#34;, sterilization of the drug container and infusor attached together sterilizes all fluid conducting passages and all primary and secondary drug contact surfaces. Depending on the needle cover design and packaging of the entire unit, these surfaces will remain absolutely sterile until the moment of use when the needle is exposed to air seconds before venipuncture. Using the fewest possible parts and attaining the maximum variable end configurations makes this item a broadly based economical product. The only cause for component difference requiring separate tooling is dosage size variation and needle size. However, they add significant substitute possibilities to the overall system. 
     From an operating room standpoint, the presence of the transparent tubular element 38, forming a chamber larger than the cannula, provides a ready visible observation of an accurate venipuncture and substantially lowers the pressure of the blood, thereby substantially reducing the possibility of the introduction of blood into the drug container. Additionally, more than one drug can be administered sequentially to the same patient without removal of the cannula from the venipuncture and when telescoped vials of the type described herein are utilized, drugs having a short life span following hydration can be pre-assembled to a needle in a rapid manner. 
     The infusor unit can be fabricated from known transparent thermoplastic materials such as polypropylene. The pistons or plugs are commonly made from an elastomeric material such as rubber while the vials can be fabricated from materials which are compatible with the drugs stored therein. In most instances, glass vials will be utilized with the exception of where piggyback installations require the molding of a probe and aperture at the normal enclosed end of the vial. There, a suitable plastic material compatible with the drug stored therein in its dehydrated condition can be used. For sterile packaging of the device, either in pre-assembled or side-by-side disassembled condition, vacuum formed packaging commonly known as blister-packs will provide the necessary sterility for storage and handling of devices of the type contemplated herein. 
     While the various embodiments disclose the basic teachings of this invention, it will be appreciated by those skilled in the art that other combinations of materials and structure can be used.