Multiple dose medication dispensing device

• US 5,938,642 A
• Filed: 01/23/1998
• Issued: 08/17/1999
• Est. Priority Date: 03/07/1995
• Status: Expired due to Term

• Current Assignee: Eli Lilly and Company
• Original Assignee: Eli Lilly and Company
• Inventors: Hodge, Andrew, Burroughs, Andrew, Hixson, Dave
• Primary Examiner(s): STRIGHT, RONALD K
• Application Number:
  US09/012,533
• Time in Patent Office: 571 Days
• Field of Search: 604/207, 604/208, 604/209, 604/211, 604/186, 604/232, 604/227, 604/246, 604/218, 604/181, 604/187, 222/309
• US Class Current: 604/208
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/582 by tactile feedback
• CPC Class Codes: A61M 5/24 Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic ampoules or carpules A61J1/06
• 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 5/31541 Means preventing setting of a dose beyond the amount remaining in the cartridge
• CPC Class Codes: A61M 5/31551 including axial movement of dose setting member
• CPC Class Codes: A61M 5/31556 Accuracy improving means
• CPC Class Codes: A61M 5/3156 using volume steps only adjustable in discrete intervals, i.e. individually distinct intervals
• CPC Class Codes: A61M 5/3157 Means providing feedback signals when administration is completed A61M5/20 takes precedence
• CPC Class Codes: A61M 5/31571 Means preventing accidental administration for automatic syringes A61M5/20
• CPC Class Codes: A61M 5/3158 performed by axially moving actuator operated by user, e.g. an injection button
• CPC Class Codes: A61M 5/31593 Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir

Abstract

A multi-use pen-shaped medication dispensing device made of a plastic material that is recyclable after the contents of the medication cartridge have been exhausted. The device is made of a minimal number of parts, which include a housing, a dial assembly, a generally cylindrical button assembly located within the proximal end of the dial assembly, an internally threaded nut, and an externally threaded leadscrew. The device is arranged so that the dial must be rotated to the zero dose position prior to setting a dose. The device includes a lockout mechanism that prevents the dial from being depressed during dosing. The device further includes a mechanism that limits the maximum dosage that can be dialed up and a mechanism that prevents the user from dialing up a dosage greater than that remaining in the cartridge.

Claims

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

a housing;

a container secured to said housing and including an inner chamber for containing the injectable product, a piston, and an exit, the injectable product contained between said piston and said exit;

a drive stem disposed in said housing and being in engagement with said piston, wherein a length of axial movement of said drive stem with respect to said housing between a pre-injection position and a post-injection position defines a stroke length of said drive stem;

means for maintaining said drive stem in engagement with said piston by preventing axial retraction of said drive stem away from said piston;

a manually adjustable dosage metering mechanism comprising a nut rotatably engaging said drive stem and a dial assembly rotatably engageable and axially engageable with said nut, said dosage metering mechanism disposed in said housing and having an initial axial position, wherein the stroke length is zero, and a dose setting axial position corresponding to a selectively adjustable positive stroke length, said dosage metering mechanism movable between said initial axial position and said dose setting axial position by movement of said dial assembly by a user;

means coupled to said dosage metering mechanism for preventing the movement of said dosage metering mechanism from said initial axial position to said dose setting axial position until said dosage metering mechanism has been set to a radial zero dose position;

a clutching mechanism operatively disposed between said nut and said dial assembly, said clutching mechanism comprising first and second clutch surfaces respectively disposed on said nut and said dial assembly, disengagement of said clutch surfaces rotatably disengaging said nut and said dial assembly in said initial axial position and engagement of said clutch surfaces engaging said nut and said dial assembly in said dose setting axial position whereby rotation of said dial assembly in said dose setting axial position repositions said nut with respect to said drive stem; and

wherein axial advancement of said dosage metering mechanism from a dose setting axial position and a positive dose radial position, towards said container to said initial position drives said drive stem from said pre-injection position to said post-injection position.

2. The apparatus of claim 1 further comprising

means in said housing for causing an audible clicking noise to be made upon axially advancing said drive assembly from said pre-injection position to said post-injection position, said means for causing noise providing an audible indication to a user that a complete dosage has been delivered.

3. The apparatus of claim 1 wherein said clutching mechanism comprises a first spline disposed on said nut and a second spline disposed on said dial assembly, said splines positioned whereby said first spline is rotatably engaged with said second spline in said dose setting axial position and said splines are rotatably disengaged in said initial axial position.

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

a housing;

a container secured to said housing and including an inner chamber for containing the injectable product, a piston, and an exit, the injectable product contained between said piston and said exit;

a drive stem disposed in said housing and being in engagement with said piston, wherein a length of axial movement of said drive stem with respect to said housing between a pre-injection position and a post-injection position defines a stroke length of said drive stem;

means for maintaining said drive stem in engagement with said piston by preventing axial retraction of said drive stem away from said piston; and

a manually adjustable dosage metering mechanism comprising a nut rotatably engaging said drive stem and a dial assembly rotationally engageable with said nut whereby said nut is axially repositionable with respect to said drive stem, said dosage metering mechanism disposed in said housing and having an initial axial position, wherein the stroke length is zero, and a selectively adjustable dose setting axial position corresponding to a selectively adjustable positive stroke length, said dosage metering mechanism movable between said initial axial position and said dose setting axial position by selective movement of said dial assembly by a user;

said dosage metering mechanism being movable in said initial axial position with respect to the housing between a non-dose setting radial position and a zero dose radial position, wherein said dose metering mechanism includes a first element that is in interfering relationship with a second element on said housing while said dosage metering mechanism is in said initial axial position and said non-dose setting radial position, thereby preventing movement of said dosage metering mechanism from said initial axial position to said dose setting axial position, and wherein said first element is not in interfering relationship with said second element while said dosage metering mechanism is in said zero dose radial position, thereby permitting said dosage metering mechanism to be moved from said initial axial position to said dose setting axial position.

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

a housing;

a container secured to said housing and including an inner chamber for containing the injectable product, a piston, and an exit, the injectable product contained between said piston and said exit;

a drive stem disposed in said housing and being in engagement with said piston, wherein a length of axial movement of said drive stem with respect to said housing between a pre-injection position and a post-injection position defines a stroke length of said drive stem;

means for maintaining said drive stem in engagement with said piston by preventing axial retraction of said drive stem away from said piston;

a nut rotatably and axially drivingly engaging said drive stem;

a generally cylindrical dial assembly disposed in said housing and operatively coupled with said nut;

said dial assembly movable axially with respect to said housing between a dose setting axial position, wherein rotation of said dial assembly rotates said nut relative to said drive stem and adjusts the stroke length of said drive stem, and an initial axial position, wherein rotation of said dial assembly does not rotate said nut relative to said drive stem and does not change the stroke length of said drive stem;

said dial assembly being rotatable with respect to said housing in said initial axial position between a non-dose setting rotational position and a zero dose rotational position;

while said dial assembly is in said initial axial position and in said non-dose setting rotational position, a first element on said dial assembly is in interfering relationship with a second element on said housing, thereby preventing said dial assembly from being moved from said initial axial position to said dose setting axial position, and wherein, upon rotation of said dial assembly to said zero dose rotational position, said first element is moved out of interfering relationship with said second element, thereby permitting said dosage metering mechanism to be moved from said initial axial position to said dose setting axial position.

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

a housing;

a container mounted within said housing and including an inner chamber for containing the injectable product, a piston, and an exit, the injectable product contained between said piston and said exit, wherein movement of said piston toward the exit defines an axis of ejection of the injectable product from the container;

a manually advanceable drive stem disposed in said housing and drivingly coupled to said piston;

means for maintaining said drive stem in engagement with said piston by preventing axial retraction of said drive stem away from said piston;

a drive assembly mounted to said housing and manually axially advanceable in said housing between a dose-setting position and an injection position for manually moving said drive stem to drive said piston within said container, said drive assembly axially retractable from said injection position to said dose-setting position for selectively adjusting a stroke length of said drive stem, said drive assembly including a nut rotatably and axially drivingly engaging said drive stem and a dial assembly operatively coupled to said nut;

locking means for axially engaging said drive assembly with respect to said housing along the axis of ejection while in said dose setting position; and

a disengaging device secured to at least one of said drive assembly and said housing and manually actuable to disengage said locking means whereby said drive assembly is axially disengaged from said housing to enable said drive assembly to be axially advanceable with respect to said housing to move said drive assembly from said dose setting position to said injection position.

7. The apparatus of claim 6, wherein said dial assembly comprises a generally cylindrical dial that is telescopingly disposed within said housing, and wherein said locking means is disposed on said dial and comprises a flexible finger that engages an internal groove in said housing while said drive assembly is in said dose-setting position to form an interference fit therebetween, thereby preventing non-rotational axial movement of said drive assembly with respect to said housing.

8. The apparatus of claim 7, wherein said disengaging device is generally cylindrical and is telescopingly disposed within said dial, said disengaging device including an enlarged diameter portion, said enlarged diameter portion biasing said flexible finger outwardly in a first position and when said disengaging device is advanced to a second position said enlarged diameter portion is in a non-biasing position and allows said finger to move radially inward out of engagement with said groove in said housing to enable said drive assembly to be axially advanced with respect to the housing.

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

a housing;

a container secured to said housing and including an inner chamber for containing the injectable product, a piston, and an exit, the injectable product contained between said piston and said exit;

a manually advanceable drive stem disposed in said housing and being in engagement with said piston, wherein a length of axial movement of said drive stem with respect to said housing between a dose-setting position and a post-injection position defines a stroke length of said drive stem;

means for maintaining said drive stem in engagement with said piston by preventing axial retraction of said drive stem away from said piston;

a drive assembly for manually driving said drive stem, said drive assembly engageably disposed within said housing and rotationally engaging said drive stem;

said drive assembly being engageably locked from non-rotational axial movement with respect to said housing while in said dose-setting position;

said drive assembly also forming a manually adjustable dosage metering mechanism movable axially without rotation between an initial axial position, wherein the stroke length is zero, and a dose setting axial position wherein the stroke length of said drive stem is selectively adjustable by a user; and

a disengaging device disposed in said housing and positioned to axially disengage said drive assembly from said housing upon initiation of an injection to enable said drive stem to move from said dose-setting position to said post-injection position.

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

a housing;

a container mounted within said housing and including an inner chamber for containing the injectable product, a piston, and an exit, the injectable product contained between said piston and the exit, wherein movement of said piston toward the exit defines an axis of ejection of the injectable product from the container;

a manually advanceable drive stem disposed in said housing and drivingly coupled to said piston;

means for maintaining said drive stem in engagement with said piston by preventing axial retraction of said drive stem away from said piston;

means in said housing for advancing said drive stem between a dose-setting position and an injection position, said advancing means including a nut threadedly engaging said drive stem;

locking means in said housing for axially interengaging said advancing means and said housing to lock said advancing means against axial movement along the axis of ejection while said advancing means is in said dose-setting position; and

disengaging means in said housing for automatically disengaging said advancing means and said housing upon actuation thereof to unlock said advancing means and enable said drive stem to be manually advanced from said dose-setting position to said injection position.

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

a housing;

a container mounted within said housing and including an inner chamber for containing a quantity of injectable product which comprises multiple doses of the injectable product, a piston, and an exit, the injectable product contained between said piston and said exit;

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

a dosage metering mechanism in said housing to establish a set dosage of injectable product to be delivered, said dosage metering mechanism comprising a dial assembly rotatable with respect to said housing to establish said set dosage, said dial assembly including at least one radially flexible protrusion that is in engagement with a helical groove formed in the inner surface of said housing, said helical groove including an end, wherein rotation of said dial assembly is stopped when said at least one radially flexible protrusion comes into engagement with said end of said helical groove, thereby establishing a predetermined maximum set dosage for a single dose, said single dose being less than said quantity of injectable product containable in said inner chamber, non-rotational axial advancement of said dosage metering mechanism driving said drive stem.

12. The apparatus of claim 11 wherein a length of axial movement of said drive stem with respect to said housing between a pre-injection position and a post-injection position defines a stroke length of said drive stem, and wherein said dosage metering mechanism is movable between an initial axial position, wherein the stroke length is zero and said protrusion is disengaged from said helical groove, and a dose setting axial position wherein said protrusion is engaged with said helical groove.

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

a housing;

a container secured to said housing and including an inner chamber for containing the injectable product, a piston, and an exit, the injectable product contained between said piston and said exit;

an externally threaded drive stem disposed in said housing and drivingly coupled to said piston;

means for maintaining said drive stem in engagement with said piston by preventing axial retraction of said drive stem away from said piston;

an internally threaded nut disposed about said drive stem;

a dial assembly disposed in said housing and coupled to said nut such that rotation of said dial assembly causes rotation of said nut with respect to said drive stem to set a desired dosage of injectable product to be delivered, said dial assembly axially engageable with said nut whereby axial advancement of said dial assembly axially advances said nut;

a clutching mechanism operatively disposed between said nut and said dial assembly, said clutching mechanism comprising first and second clutch surfaces respectively disposed on said nut and said dial assembly, disengagement of said clutch surfaces rotatably disengaging said dial assembly and said nut when said dial assembly is in an initial axial position and engagement of said clutch surface rotatably engaging said dial assembly and said nut when said dial assembly is in a dose-setting axial position; and

means on at least one of said nut and said drive stem for preventing rotation of said nut with respect to said drive stem as said nut engages an end of an external threaded surface of said drive stem, thereby providing an indication to a user that an insufficient dosage of injectable product remains in said container.

14. An apparatus for delivering an injectable product, said apparatus comprising:

a housing;

a container disposed within said housing, said container having an inner chamber, a piston and an exit, the injectable product contained between said piston and said exit;

an externally threaded drive stem disposed in said housing and in engagement with said piston;

a tang disposed in said housing and axially engaging said drive stem whereby said drive stem continuously engages said piston;

an internally threaded nut engaging said drive stem, rotation of said nut axially repositioning said nut on said drive stem;

a dial assembly disposed in said housing, said dial assembly being axially engageable and rotationally engageable with said nut; and

a spline disposed on one of said dial assembly and said nut, said spline rotationally engaging said dial assembly with said nut while said dial assembly is in a dose-setting axial position, axial advancement of said dial assembly to an initial axial position from a dose-setting axial position axially engaging said dial assembly and said nut whereby said drive stem is axially advanceable by the axial advancement of said dial assembly, said axial advancement of said dial assembly to said initial axial position disengaging said spline whereby said dial assembly and said nut are rotationally disengaged in said initial axial position.

15. The apparatus of claim 14 wherein said housing further comprises a finger and said dial assembly further comprises a groove, said finger and said groove being axially engageable while said dial assembly is in said initial axial position, axial engagement of said groove and said finger preventing axial retraction of said dial assembly from said initial axial position to said dose setting axial position while said dial assembly is in a non-zero dose radial position, said finger axially disengaged from said groove in said initial axial position while said dial assembly is in a zero dose radial position whereby said dial assembly is axially moveable to said dose setting axial position in said zero dose radial position.

16. The apparatus of claim 14 wherein said dial assembly further comprises a finger engageable with a helical groove on said housing, engagement of said finger and said groove preventing non-rotational axial movement of said dial assembly relative to said housing, disengagement of said finger permitting non-rotational axial advancement of said dial assembly.

17. The apparatus of claim 14 wherein said spline is disposed on said nut and a second spline disposed on said dial assembly is engageable with said spline whereby engagement of said second spline with said spline rotationally engages said dial assembly with said nut.