Manifold medication injection apparatus and method

• US 5,505,704 A
• Filed: 06/01/1995
• Issued: 04/09/1996
• Est. Priority Date: 04/02/1993
• Status: Expired due to Term

• Current Assignee: Eli Lilly and Company
• Original Assignee: Eli Lilly and Company
• Inventors: Karshmer, David L., Stringer, Christopher J., Schoenberg, Stephen J., Marsh, Matthew, Lada, Christopher O., Pawelka, Gerhard E. F.
• Primary Examiner(s): Rosenbaum, C. Fred
• Assistant Examiner(s): VANOVER, PERRY
• Application Number:
  US08/458,013
• Time in Patent Office: 313 Days
• Field of Search: 604/82, 604/191, 604/187, 604/207, 604/208-211, 604/186, 604/218, 604/228, 604/236, 604/232-233, 604/235
• US Class Current: 604/191
• CPC Class Codes: A61M 2205/583 by visual feedback
• CPC Class Codes: A61M 5/19 having more than one chamber , e.g. including a manifold coupling two parallelly aligned syringes through separate channels to a common discharge assembly surgical glue applicators A61B17/00491
• CPC Class Codes: A61M 5/2448 comprising means for injection of two or more media, e.g. by mixing
• CPC Class Codes: A61M 5/31535 Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose
• CPC Class Codes: A61M 5/31536 Blocking means to immobilize a selected dose, e.g. to administer equal doses
• CPC Class Codes: A61M 5/31541 Means preventing setting of a dose beyond the amount remaining in the cartridge
• CPC Class Codes: A61M 5/31543 piston rod reset means, i.e. means for causing or facilitating retraction of piston rod to its starting position during cartridge change
• CPC Class Codes: A61M 5/31553 without axial movement of dose setting member
• CPC Class Codes: A61M 5/31563 interacting with a displaceable stop member
• CPC Class Codes: A61M 5/3158 performed by axially moving actuator operated by user, e.g. an injection button
• CPC Class Codes: A61M 5/31581 performed by rotationally moving or pivoting actuator operated by user, e.g. an injection lever or handle

Abstract

A hand-held dual liquid medication injector have dual, bi-directional dosage metering mechanisms for permitting a variable dosage amount for each cartridge of liquid medication. The medications are mixed within a manifold having a valved mixing chamber and are injected via a single cannula. The mixing chamber is valved such that backflow of mixed or unmixed medications into the cartridges is prevented. An injection mechanism, independent of the metering mechanism, loads and injects the liquid medication. In one embodiment, downward movement of the injection mechanism during injection is translated into horizontal movement by the plunger mechanism. In another embodiment, a power-assisted plunger mechanism accomplishes injection.

Claims

1. A medication dispensing device for effecting the simultaneous delivery of two injectable products, comprising:

a housing;

a first cartridge received in said housing for containing and sealing a first injectable product therein, said first cartridge having a first exit end and including a first plunger therein;

a second cartridge received in said housing for containing and sealing a second injectable product therein, said second cartridge having a second exit end and including a second plunger therein;

a first dosage metering mechanism disposed in said housing and including a first dosage adjuster coupled to a first plunger-engageable member such that upon adjustment of said first dosage adjuster, said first member is axially advanceable a first distance with respect to said housing to establish a first set dosage of injectable product to be delivered without effecting delivery of the first injectable product;

a second dosage metering mechanism disposed in said housing and including a second dosage adjuster coupled to a second plunger-engageable member such that upon adjustment of said second dosage adjuster, said second member is axially advanceable a second distance with respect to said housing to establish a second set dosage of injectable product to be delivered without effecting delivery of the second injectable product;

a manifold secured to said first and second exit ends of said first and second cartridges, respectively, for enabling the mixing of said first and second set dosages of said first and second injectable products upon delivery from said respective cartridges into said manifold, said manifold being in fluid communication with said first and second cartridges and containing a common exit for enabling the mixed injectable product to be delivered to a user; and

an injector mechanism coupled to said first and second members for simultaneously axially advancing said first and second members a distance sufficient to engage and axially advance said first and second plungers, respectively, to effect simultaneous delivery of said first and second set dosages into said manifold and out through said cannula.

2. The apparatus of claim 1, wherein said injector mechanism includes a carrier, wherein said first and second members are secured to said carrier and axially movable therewith, said carrier being axially advanceable upon actuation of said injector mechanism to simultaneously advance said members to effect simultaneous delivery of said first and second set dosages.

3. The apparatus of claim 1, wherein the axial advancement of said first and second plungers in said first and second cartridges, respectively, defines a first axis of delivery and a second axis of delivery, respectively, said first and second axes of delivery being generally parallel to one another, wherein said injector mechanism includes a hand-operated actuator movable in a direction transverse to said axes of delivery to effect delivery of the mixed injectable product.

4. The apparatus of claim 1, wherein the axial advancement of said first and second plungers in said first and second cartridges, respectively, defines a first axis of delivery and a second axis of delivery, respectively, said first and second axes of delivery being generally parallel to one another, wherein said injector mechanism includes a hand-operated actuator movable in a direction generally parallel to said axes of delivery to effect delivery of the mixed injectable product.

5. The apparatus of claim 4, wherein a power assist spring is secured to said housing and coupled to said first and second members said spring being preloaded to urge said first and second members axially toward said first and second cartridges, respectively, upon actuation of said injection mechanism, wherein said power assist spring aids the user in completion of the injection.

6. The apparatus of claim 1, wherein said injector mechanism operates independently of said first and second metering mechanisms.

7. The apparatus of claim 1, wherein said first and second dosage adjustors are rotatable to effect advancement of said first and second members.

8. The apparatus of claim 7, wherein said first and second dosage adjusters are rotatable in both a clockwise direction and a counterclockwise direction thereby enabling each of said respective first and second members to be translated axially forwardly and rearwardly to enable a user to selectively increase and decrease said first and second set dosages prior to actuating said injector mechanism.

9. The apparatus of claim 1, wherein said first and second members are leadscrews coupled to said respective first and second dosage metering mechanisms in such a manner that adjustment of each said respective dosage adjustor causes said respective leadscrew to translate axially in a non-rotary manner within said housing.

10. An apparatus for effecting delivery of an injectable product, comprising:

a housing;

a cartridge received in said housing for containing and sealing an injectable product therein, said cartridge including an exit end and a plunger axially movable in said cartridge to define an axis of ejection of the injectable product from said cartridge;

a manually adjustable dosage metering mechanism disposed in said housing for enabling a user to selectively set a dosage of the injectable product to be delivered without effecting delivery of the injectable product from said cartridge; and

a delivery mechanism including an elongate member for engaging and axially advancing said plunger a distance sufficient to cause said set dosage to be delivered out of said cartridge, said delivery mechanism including a hand operated actuator movable in a direction transverse to the axis of ejection, wherein each incremental movement of said actuator causes a corresponding incremental movement of said elongate member, wherein a predetermined movement of said actuator in said transverse direction causes delivery of said set dosage.

11. The apparatus of claim 10, wherein said dosage metering mechanism includes a dosage adjustor coupled to a leadscrew such that upon rotation of said dosage adjustor, said leadscrew is axially advanceable a given distance with respect to said housing to establish said set dosage of injectable product to be delivered without effecting delivery of the injectable product.

12. A medication dispensing device for effecting the simultaneous delivery of two injectable products through a single cannula, comprising:

a housing;

a first cartridge received in said housing for containing and sealing a first injectable product therein, said first cartridge having a first exit end and including a first plunger therein;

a second cartridge received in said housing for containing and sealing a second injectable product therein, and said second cartridge having a second exit end and including a second plunger therein;

a dosage metering mechanism disposed in said housing to establish a first set dosage of the first injectable product to be delivered, and a second set dosage of the second injectable product to be delivered;

an injector mechanism to engage and axially advance said first and second plungers to effect simultaneous delivery of said first and second set dosages out of said first and second cartridges, respectively; and

a manifold secured to said first and second exit ends of said first and second cartridges, respectively, for enabling the mixing of said first and second set dosages of said first and second injectable products upon delivery from said respective cartridges into said manifold, said manifold comprising a front housing, a rear housing including a first cannula extending into said first cartridge and a second cannula extending into said second cartridge, and a rubber septum disposed between said front and rear housings, said septum comprising a substantially flat surface adjacent ends of said first and second cannulas, said front housing including a delivery needle therein for delivery of injectable product through said delivery needle, wherein a first fluid path for the first injectable product is formed in said manifold from said first cannula to said delivery needle and a second fluid path for the second injectable product is formed in said manifold from said second cannula to said delivery needle, wherein a first flat portion of a first surface of said septum is in fluid-tight engagement with a first flat sealing surface of said rear housing to define a first pressure-actuated valve portion in said first fluid path and wherein a second flat portion of a second surface of said septum is in fluid-tight engagement with a second flat sealing surface of said rear housing to define a second pressure-actuated valve portion in said second fluid path, said first and second valve portions being biased in a closed position to prevent the flow of injectable product therethrough, said first and second valve portions being flexible enough to open to permit the flow therethrough of the first and second injectable products, respectively, upon the expulsion of the first and second injectable products out of said first and second cannulas, respectively.

13. The device of claim 12, wherein said front housing includes an elongate recessed portion formed therein to define a channel, said channel being part of said first and second fluid paths and in engagement with said first and second valve portions of said septum.

14. The device of claim 12, wherein said septum includes a first opening extending therethrough in communication with said first flow path, a second opening extending therethrough in communication with said second flow path and a third opening extending therethrough, said third opening receiving said delivery needle.

15. An apparatus for the delivery of an injectable product, comprising:

a housing;

a container mounted within said housing and including a plunger, an exit and an injectable product between said plunger and said exit;

a drive stem disposed in said housing and drivingly coupled to said plunger;

a drive assembly mounted to said housing and axially movable in said housing between a dose-setting position and an injection position for moving said drive stem to drive said plunger within said container, said drive assembly including a first ratchet element; and

a dose setting assembly coupled to said drive assembly to establish a set dosage of injectable product to be delivered, said dose setting assembly including an indicator element being movable from a zero dose reference position against a biasing force to a specific dose reference position upon the setting of a desired dose to be delivered, said dose setting assembly including a mechanism in engagement with said indicator element to maintain said indicator element in said specific dose position while said drive assembly is in said dose-setting position, said mechanism being movable out of engagement with said indicator element upon movement of said drive assembly from said dose-setting position to said injection position, thereby enabling said indicator element to be automatically biased back to its zero dose reference position.

16. An apparatus for the delivery of an injectable product, comprising:

a housing;

a container mounted within said housing and including a plunger, an exit and an injectable product between said plunger and said exit;

a drive stem disposed in said housing and drivingly coupled to said plunger;

a drive assembly mounted to said housing and axially movable in said housing between a dose-setting position and an injection position for moving said drive stem to drive said plunger within said container, said drive assembly including a first element; and

a dose setting assembly coupled to said drive assembly to establish a set dosage of injectable product to be delivered, said dose setting assembly comprising a rotatable element including a dose setting knob and a second element, said drive assembly being positioned such that said first element is in locking engagement with said second element while said drive assembly is in said dose-setting position, and said first element is moved into unlocked relationship with said second element upon movement of said drive assembly from said dose-setting position to said injection position;

while said drive assembly is in said dose-setting position, said rotatable element is rotatable from a predetermined initial radial position against the bias of a spring to a selective final radial position for selectively setting the dosage of injectable product to be delivered, wherein said rotatable element is biased back to said initial radial position upon movement of said drive assembly from said dose-setting position to said injection position due to the disengagement of said first member from said second member.

17. An apparatus for the delivery of an injectable product, comprising:

a housing;

a container mounted to said housing and including a plunger, an exit and an injectable product between said plunger and said exit;

a drive stem disposed in said housing and drivingly coupled to said plunger;

a drive assembly mounted to said housing and axially movable in said housing between a pre-injection position and a post-injection position for moving said drive stem to drive said plunger within said container, said drive assembly including a first ratchet element, and a tubular element coupled to said drive stem such that said tubular element is rotatable with respect to said drive stem, wherein relative rotation between said tubular element and said drive stem controls the amount of telescopic extension of said drive stem from said tubular element to establish a set dosage of injectable product to be delivered, said drive stem being axially movable with said tubular element between said pre-injection position and said post-injection position; and

a dose setting assembly coupled to said drive assembly and comprising a rotatable element having an end in the form of a dose setting knob and a second ratchet element engageable with said first ratchet element while said drive assembly is in said pre-injection position, wherein said dose setting knob is coupled to said tubular element while said drive assembly is in said pre-injection position so that rotation of said knob with respect to said housing results in rotation of said tubular element, said rotatable element being rotatable against the force of a spring from an initial radial position to a selective final radial position for selectively advancing said drive stem to set the dosage of injectable product to be delivered, said first ratchet element being spaced from said second ratchet element while said drive assembly is in said post-injection position, whereby said spring biases said rotatable element from said final radial position to said initial radial position upon movement of said drive assembly from said pre-injection position to said post-injection position.

18. The apparatus of claim 17, wherein said plunger is axially movable in said container toward said exit to define an axis of ejection of said injectable product, wherein said drive assembly includes an actuator movable in a direction transverse to said axis of ejection for moving said drive assembly between said pre-injection position to said post-injection position.

19. The apparatus of claim 17, wherein said rotatable member includes a plurality of numerals spaced about said rotatable member, wherein said housing includes an opening therein and said rotatable member is arranged in said housing such that a numeral appears in said opening, thereby indicating to the user the number of dosage units constituting said set dosage.

20. The apparatus of claim 19, wherein the numeral 0 appears in said opening while said rotatable member is in its initial radial position.

21. An apparatus for the delivery of an injectable product, comprising:

a housing;

a container mounted to said housing and including a plunger, an exit and an injectable product between said plunger and said exit;

plunger-engagement means disposed in said housing for drivingly engaging said plunger;

drive means mounted to said housing for moving said plunger-engagement means between a pre-injection position and a post-injection position to drive said plunger within said container, said drive means including a first element, and a nut means coupled to said plunger-engagement means for rotation with respect to said plunger-engagement means, wherein relative rotation between said nut means and said plunger-engagement means controls the amount of telescopic extension of said plunger-engagement means from said nut means to establish a set dosage of injectable product to be delivered, said plunger-engagement means being axially movable with said nut means between said pre-injection position and said post-injection position; and

dose setting means for setting a dosage of injectable product to be delivered, said dose setting means coupled to said drive means and comprising a rotatable element including a dose setting knob and a second element engageable with said first element while said drive means is in said pre-injection position, wherein said dose setting knob is coupled to said nut means while said plunger-engagement means is in said pre-injection position so that rotation of said knob with respect to said housing results in rotation of said nut means, said rotatable element being rotatable against the force of spring means from an initial radial position to a selective final radial position for selectively advancing said plunger-engagement means to set the dosage of injectable product to be delivered, said first ratchet element being spaced from said second ratchet member while said plunger-engagement means is in said post-injection position, whereby said spring means biases said rotatable element from said final radial position to said initial radial position upon movement of said plunger-engagement means from said pre-injection position to said post-injection position.

22. The apparatus of claim 21, wherein said plunger is axially movable in said container toward said exit to define an axis of ejection of said injectable product, wherein said drive means includes an actuator movable in a direction transverse to said axis of ejection for moving said plunger-engagement means between said pre-injection position to said post-injection position.

23. The apparatus of claim 21, wherein said rotatable member includes a plurality of numerals spaced about said rotatable member, wherein said housing includes an opening therein and said rotatable member is arranged in said housing such that a numeral appears in said opening, thereby indicating to the user the number of dosage units constituting said set dosage.

24. The apparatus of claim 23, wherein the numeral 0 appears in said opening while said rotatable member is in its initial radial position.

25. An apparatus for the delivery of an injectable product, comprising:

a housing;

a container received in said housing and including a plunger, an exit and an injectable product between said plunger and said exit;

a drive stem disposed in said housing and drivingly coupled to said plunger; and

a drive assembly mounted to said housing and axially movable in said housing for moving said drive stem to drive said plunger within said container;

wherein a locking mechanism is engageable with said drive stem and configured to restrict rotation of said drive stem with respect to said housing, said locking mechanism being in engagement with said drive stem while said container is securely mounted in said housing to prevent rotation of said drive stem with respect to said housing, said locking mechanism being automatically disengaged from said drive stem upon removal of said container from said housing, thereby permitting said drive stem to be rotated with respect to said housing.

26. An apparatus for the delivery of an injectable product, comprising:

a housing having a proximal end and a distal end;

a container received in said distal end of said housing and including a plunger, an exit and an injectable product between said plunger and said exit;

a drive stem disposed in said housing and drivingly coupled to said plunger;

a dosage metering mechanism disposed in said housing to establish a first set dosage of the first injectable product to be delivered; and

a drive assembly mounted to said housing and axially movable in said housing for reciprocatingly moving said drive stem to drive said plunger within said container,

wherein a locking mechanism is engagable with said drive stem and configured to prevent axial movement of said drive stem toward said proximal end of said housing independent of said dosage metering mechanism and said drive assembly, said locking mechanism being in engagement with said drive stem while said container is securely mounted in said housing to prevent said independent axial movement of said drive stem with respect to said housing, said locking mechanism being automatically disengaged from said drive stem upon removal of said container from said housing, thereby permitting said drive stem to be axially moved toward the proximal end of said housing independent of said dosage metering mechanism and drive assembly.

27. An apparatus for the delivery of an injectable product, comprising:

a housing;

a container received in said housing and including a plunger, an exit and an injectable product between said plunger and said exit;

a drive stem disposed in said housing and drivingly coupled to said plunger; and

a drive assembly mounted to said housing and axially movable in said housing for moving said drive stem to drive said plunger within said container,

wherein a rotatable piece is secured to said drive stem for rotation therewith, and a locking sleeve is disposed about said drive stem and configured to restrict rotation of said rotatable piece with respect to said housing, said rotatable piece and said locking sleeve being biased in unlocked relationship with one another, said rotatable piece and said locking sleeve being forced into locked engagement with one another while said container is mounted to said housing to prevent rotation of said rotatable piece and said drive stem with respect to said housing, said rotatable piece and said locking sleeve being automatically disengaged from one another upon removal of said container from said housing, thereby permitting said rotatable piece and said drive stem to be rotated with respect to said housing.

28. The apparatus of claim 27, wherein a spring is positioned in said housing with respect to said rotatable piece and said locking means to apply a biasing force sufficient to separate a first locking element of said rotatable piece from a second locking element of said locking means, said spring means being positioned in said housing such that upon said container being secured to said housing end, said spring means is compressed sufficiently to permit said rotatable piece to lockingly engage with said locking means.

29. The apparatus of claim 27, wherein said rotatable piece includes a first set of ratchet teeth and said locking means includes a second set of ratchet teeth, wherein said first set of ratchet teeth are in engagement with said second set of ratchet teeth while said container is mounted to said housing.

30. The apparatus of claim 27, wherein said plunger-engagement means is moveable axially from said housing end and toward a second and opposite housing end upon said container being removed from said housing.

31. An apparatus for the delivery of an injectable product, comprising:

a housing;

a container received in said housing and including a plunger, an exit and an injectable product between said plunger and said exit;

plunger-engagement means disposed in said housing for drivingly engaging said plunger; and

drive means mounted to said housing and axially movable in said housing for moving said plunger-engagement means to drive said plunger within said container,

wherein a rotatable piece is secured to said drive stem for rotation therewith, and a locking means is disposed about said drive stem and configured to restrict rotation of said rotatable piece with respect to said housing, said rotatable piece and said locking means being in unlocked relationship with one another, said rotatable piece and said locking means being forced into locked engagement with one another while said container is mounted to said housing to prevent rotation of said rotatable piece and said plunger-engagement means with respect to said housing, said rotatable piece and said locking means being automatically disengaged from one another upon removal of said container from said housing, thereby permitting said rotatable piece and said plunger-engagement means to be rotated with respect to said housing.

32. An apparatus for effecting delivery of an injectable product, comprising:

a first cartridge for containing and sealing a first injectable product therein, said first cartridge having a first exit end and including a first plunger axially movable in said first cartridge to define a first axis of ejection of the first injectable product from said first cartridge;

a second cartridge for containing and sealing a second injectable product therein, said second cartridge having a second exit end and including a second plunger axially movable in said second cartridge to define a second axis of ejection of the second injectable product from said second cartridge;

a housing having a proximal end and a distal end, wherein said first and second cartridges are mounted to said distal end;

a manually operable dosage metering mechanism disposed in said housing for enabling a user to selectively set a dosage of at least one of the first and second injectable products to be delivered without effecting delivery of the respective injectable product from said respective cartridge;

a delivery mechanism for simultaneously axially advancing said first and second plungers a distance sufficient to effect simultaneous delivery of said first and second set dosages out of said respective cartridges, said delivery mechanism including an actuator movable in a direction transverse to said axes of delivery, wherein movement of said actuator in said transverse direction causes delivery of said first and second set dosages; and

a manifold secured to said first and second exit ends of said cartridges for enabling the mixing of said set dosages of said first and second injectable products and the delivery of a mixed injectable product upon movement of said actuator, said manifold including a cannula extending into each of said cartridges and a common exit in fluid communication with said cartridges for enabling the mixed injectable product to be delivered to a user.

33. The apparatus of claim 32, wherein said first and second members are secured to a carrier and are axially moveable with said carrier, said carrier being axially advanceable upon actuation of said actuator to simultaneously axially advance said members to engage and axially advance said respective plungers in said cartridges to effect simultaneous delivery of said set dosages.

34. The apparatus of claim 32, wherein said actuator includes a side plate, wherein said side plate is coupled to a driving pin associated with each said member such that upon actuation of said actuator, said side plate and pin are moved axially forwarding thus causing said members to be moved axially forwardly to engage and axially advance said respective plungers.

35. A method of delivering a selected dosage of injectable product, the method comprising the steps of:

rotating a knob extending from an injector housing to set a dosage of injectable product to be delivered out of a container mounted to an end of the housing, wherein the injectable product is in the container between a plunger and an exit end of the container, wherein movement of the plunger toward the exit end defines an axis of ejection of the injectable product from the container; and

continuously moving an actuator in a direction transverse to the axis of ejection to move the plunger and effect delivery of the injectable product.

36. The method of claim 35, wherein the step of continuously moving the actuator includes moving the actuator through a given angular range of motion, wherein incremental movement of the actuator results in a corresponding incremental axial advancement of a drive assembly which carries a plunger-engaging stem.

37. The method of claim 35, wherein the step of rotating includes rotating the knob in a first rotational direction to increase the set dosage and then in a second and opposite rotational direction in order to decrease the set dosage.

38. The method of claim 35, wherein movement of the actuator causes the knob to be rotated back to an initial rotational position.

39. A method of delivering a selected dosage of mixed injectable product, the method comprising the steps of:

rotating a first knob of a first dosage metering mechanism disposed in an injector housing to set a first set dosage of first injectable product to be delivered out of a first container mounted in the housing, wherein the first injectable product is in the first container between a first plunger and a first exit end of the first container, wherein the first plunger is movable toward the first exit end along a first axis of ejection of the first injectable product from the first container;

rotating a second knob of a second dosage metering mechanism disposed in the injector housing to set a second set dosage of second injectable product to be delivered out of a second container mounted in the housing, wherein the second injectable product is in the second container between a second plunger and a second exit end of the second container, wherein the second plunger is movable toward the second exit end along a second axis of ejection of the second injectable product from the second container, the second axis being generally parallel to the first axis; and

moving an actuator in a direction transverse to the first and second axes of ejection to simultaneously axially advance first and second plunger-engagement members in the housing to axially advance the first and second plungers, respectively, to effect simultaneous delivery of the first and second set dosages into a manifold attached to the first and second exit ends of the first and second containers and out through a needle extending from the manifold.

40. The method of claim 39, wherein the step of moving the actuator includes moving the actuator through a given angular range of motion, wherein incremental movement of the actuator results in a corresponding incremental axial advancement of a drive assembly which carries the first and second members.

41. The method of claim 39, wherein the step of rotating includes rotating at least one of the first and second knobs in a first rotational direction to increase the respective set dosage and then in a second and opposite rotational direction in order to decrease the respective set dosage.

42. The method of claim 39, wherein movement of the actuator causes at least one of the first and second knobs to be rotated back to an initial rotational position.

43. A method of delivering a selected dosage of injectable product, wherein the injectable product is in the container between a plunger and an exit end of the container, wherein movement of the plunger toward the exit end defines an axis of ejection of the injectable product from the container, the method comprising the steps of:

moving a wing mechanism through a given angular range of motion from a first angular position to a second angular position, wherein movement of the wing is in a direction transverse to the axis of ejection;

rotating a knob of a dosage metering mechanism disposed in an injector housing to set a dosage of injectable product to be delivered out of the container mounted to an end of the housing; and

after rotation of the knob, moving the wing mechanism from the second position to the first position to effect delivery of the injectable product.

44. The method of claim 43, wherein the step of rotating includes rotating the knob in a first rotational direction to increase the set dosage and then in a second and opposite rotational direction in order to decrease the set dosage.

45. The method of claim 43, wherein movement of the wing mechanism from the second position to the first position causes the knob to be rotated back to an initial rotational position.

46. The method of claim 43, including the step of removing the container from the housing while the wing mechanism is in the first position.

47. The method of claim 46, including the step of attaching a second container to the housing.

48. The method of claim 47, wherein the step of attaching the second container to the housing includes the steps of causing the plunger to engage a plunger-engagement member in the injector housing, forcing the plunger-engagement member to translate axially within the housing toward the knob, and securing the second container within the housing.

49. A method of delivering a selected dosage of injectable product, the method comprising the steps of:

rotating a knob of a dosage metering mechanism disposed in an injector housing to set a dosage of injectable product to be delivered out of a container mounted to an end of the housing;

applying a force to an actuator to simultaneously axially advance a plunger-engagement stem to engage and axially advance a plunger to effect delivery of the set dosage from the container; and

causing a supplemental force to be applied to the plunger-engagement stem upon application of the force to the actuator, wherein the supplemental force aids in the axial advancement of the plunger-engagement stem.

50. A method of delivering a selected dosage of two injectable products, the method comprising the steps of:

rotating a first knob of a first dosage metering mechanism disposed in an injector housing to set a first set dosage of first injectable product to be delivered out of a first container mounted to an end of the housing;

rotating a second knob of a second dosage metering mechanism disposed in the injector housing to set a second dosage of a second injectable product to be delivered out of a second container mounted to the end of the housing;

applying a force to an actuator to simultaneously axially advance first and second plunger-engagement stems to engage and axially advance first and second plungers to effect simultaneous delivery of the first and second set dosages from the first and second containers, respectively; and

causing a supplemental force to be applied to the first and second plunger-engagement stems upon application of the force to the actuator, wherein the supplemental force aids in the axial advancement of the first and second plunger-engagement stems.

51. A method of delivering a selected dosage of injectable product, the method comprising the steps of:

attaching a variable volume container of injectable product to a housing, thereby causing a plunger-engagement stem within the housing to become locked against rotation with respect to the housing;

setting a dosage of injectable product to be delivered out of the container;

moving an actuator to effect nonrotating axial advancement of the plunger-engagement stem to effect delivery of the set dosage of injectable product out of an exit end of the container;

removing the container from the housing thereby automatically enabling the plunger-engaging stem to rotate with respect to the housing; and

causing the plunger-engaging stem to rotate with respect to the housing and simultaneously axially move toward an opposite end of the housing.

52. The method of claim 51, including the step of attaching a second container to the housing, thereby automatically causing the plunger-engaging stem to axially move toward the opposite end of the housing and then become locked against rotation with respect to the housing.

53. A medication dispensing device for effecting the simultaneous delivery of two injectable products, comprising:

a housing;

a first cartridge received in said housing for containing and sealing a first injectable product therein, said first cartridge having a first exit end and including a first plunger therein;

a second cartridge received in said housing for containing and sealing a second injectable product therein, said second cartridge having a second exit end and including a second plunger therein;

means disposed in said housing for enabling a user to establish a first set dosage of said first injectable product and a second set dosage of said second injectable product to be delivered without effecting delivery of the first and second injectable products, respectively;

a manifold secured to said first and second exit ends of said first and second cartridges, respectively, for enabling the mixing of said first and second set dosages of said first and second injectable products upon delivery from said respective cartridges into said manifold, said manifold being in fluid communication with said first and second cartridges and containing a common exit for enabling the mixed injectable product to be delivered to a user; and

an injector mechanism coupled to said first and second cartridges for simultaneously axially advancing said first and second plungers to effect simultaneous delivery of said first and second set dosages into said manifold and out through said cannula.

54. An apparatus for effecting delivery of an injectable product, comprising:

a housing;

a cartridge received in said housing for containing and sealing an injectable product therein, said cartridge including an exit end and a plunger axially movable in said cartridge to define an axis of ejection of the injectable product from said cartridge;

means disposed said housing for enabling a user to selectively set a dosage of the injectable product to be delivered without effecting delivery of the injectable product from said cartridge; and

a delivery mechanism including an elongate member for engaging and axially advancing said plunger a distance sufficient to cause said set dosage to be delivered out of said cartridge, said delivery mechanism including a hand operated actuator movable in a direction transverse to the axis of ejection, wherein of said actuator in said transverse direction causes delivery of said set dosage.

55. A method of delivering a selected dosage of mixed injectable product, the method comprising the steps of:

actuating a dosage metering mechanism disposed in an injector housing to set a set dosage of injectable product to be delivered out of a container mounted to the housing, wherein the injectable product is in the container between a plunger and an exit end of the container, wherein movement of the plunger toward the exit end defines an axis of ejection of the injectable product from the container; and

moving an actuator in a direction transverse to the axis of ejection to axially advance the first member to axially advance the first plunger to effect delivery of the set dosage out through a needle extending from the exit end.