Injection system

• US 6,277,097 B1
• Filed: 03/20/1998
• Issued: 08/21/2001
• Est. Priority Date: 03/25/1997
• Status: Expired due to Fees

• Current Assignee: Novo Nordisk A/S
• Original Assignee: Novo Nordisk A/S
• Inventors: Larsen, Andre, Klitmose, Lars Peter, Mikkelsen, Soren
• Primary Examiner(s): Nguyen, Anhtuan T.
• Assistant Examiner(s): Sirmons, Kevin C.
• Application Number:
  US09/045,314
• Publication Number:
  US 20010020155A1
• Time in Patent Office: 1,250 Days
• Field of Search: 604/186, 604/200, 604/201, 604/202, 604/206-211, 604/232, 604/195, 604/187, 604/415, 604/82, 604/87
• US Class Current: 604/187
• CPC Class Codes: A61J 1/201 having one piercing end
• CPC Class Codes: A61J 1/2065 having aligning and guiding means
• CPC Class Codes: A61J 1/2096 Combination of a vial and a syringe for transferring or mixing their contents
• CPC Class Codes: A61M 2005/2411 from the front
• 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 5/2448 comprising means for injection of two or more media, e.g. by mixing
• CPC Class Codes: A61M 5/31553 without axial movement of dose setting member
• CPC Class Codes: A61M 5/3156 using volume steps only adjustable in discrete intervals, i.e. individually distinct intervals
• CPC Class Codes: A61M 5/31586 performed by rotationally moving or pivoted actuator, e.g. an injection lever or handle
• CPC Class Codes: A61M 5/3202 Devices for protection of the needle before use, e.g. caps A61M5/50 takes precedence; for infusion spikes A61M5/1626; protectors for sharps A61B50/3001

Abstract

An injection system for preparing a mixture of a solvent and a medicament and for subsequent dosed injection of the mixture comprises a syringe accommodating an ampoule (7) in which a liquid is stored between a membrane (8) dosing one end of the ampoule (7) and a piston (6) which can by a piston rod (3) be forced into the ampoule (7) to press out a dose of the liquid. The piston rod (3) and the piston (6) has mutual engaging threads (4, 5) by which the piston (6) is coupled to the piston rod (3) to follow this rod in both axial directions. An outer thread (30) engaging an inner thread (29) in a housing is provided on a part (28) of the piston rod (3) so that rotation of the piston rod (3) will screw this rod and the piston (6) into the ampoule (7). A detent (18) ensures that the piston rod (3) is only rotated in a dose administering direction. However, the thread (30) of the piston rod (3) can be disengaged from the thread (29) of the housing to set the piston rod (3) free to be moved in a proximal direction.

Claims

1. An injection system for use in preparing a mixture of a solvent and a medicament and for subsequent dosed injection of the mixture, the system comprising a syringe having a housing with proximal and distal ends, and a replaceable ampoule secured relative to the syringe housing, wherein the ampoule includes a first end closed by a pierceable membrane, a second end closed by a piston having a first coupling element, and a solvent stored between the membrane and piston;

and wherein the syringe comprises;

means located at the distal end of the housing for mounting a disposable needle;

a piston rod which is supported in the housing for axial movement and which includes a second coupling element which detachably couples the piston rod to the piston, such that the piston follows movement of the piston rod in both axial directions;

a dose setting and injection mechanism supported by the housing for setting doses and for advancing the piston rod in a distal direction to inject a set dose;

a disengageable coupling between the housing and the piston rod to allow movement of the piston rod in the distal direction by means of the dose setting and injection mechanism to eject solvent from the ampoule to mix with a medicament, but to prevent movement of the piston rod in a proximal direction, when an ampoule is secured to the syringe; and

a release mechanism which can be activated for selectively releasing the disengageable coupling between the piston rod and the housing while an ampoule is secured to the syringe to allow the piston rod to move in the proximal direction to suck back a mixture into the ampoule, and deactivated to re-engage the disengageable coupling to make movement of the piston rod depend on the dose setting and injection mechanism to prepare the system for injecting such mixture.

2. A system according to claim 1, wherein the first and second coupling elements comprise threads.

3. A system according to claim 1, wherein the syringe housing includes a stop, wherein the dose setting and injection mechanism includes a member which abuts the stop to limit the movement of the piston rod in the distal direction, wherein the member can be rotated in a first rotational direction away the stop to set a dose, the angle of rotation being proportional to the dose set, and wherein the member, to inject the dose, can be rotated in a second rotational direction back into engagement with the stop.

4. A system according to claim 1, wherein the syringe housing has an inner thread, wherein the disengeable coupling includes a driver element having an outer thread which selectively engages the inner thread, and a unidirectional coupling between the dose setting and injection member and the piston rod which coupling transmits rotation of the dose setting and injection member to the piston rod only when the member rotates in the second rotational direction, wherein the driver element, responsive to being rotated in the second rotational direction, moves the piston rod in the distal direction, and wherein the release mechanism is coupled to the driver element to allow the thread of the driver element to be drawn out of engagement with the inner thread of the syringe housing to allow the piston rod to be moved in a proximal direction.

5. A method of preparing a mixture of a solvent and a medicament and for subsequent dosed injection of the mixture, comprising the steps of:

providing a syringe having a housing with proximal and distal ends, a piston rod which is supported in the housing for axial movement, a dose setting and injection mechanism supported by the housing for setting doses and for advancing the piston rod in a distal direction to inject a set dose, a disengageable coupling between the housing and the piston rod to allow movement of the piston rod in the distal direction, but to prevent movement of the piston rod in the proximal direction, when an ampoule is secured to the syringe, and a release mechanism for selectively releasing the disengageable coupling between the piston rod and the housing, while an ampoule is secured to the syringe, to allow the piston rod to move in the proximal direction;

securing a replaceable ampoule relative to the syringe housing, wherein the ampoule includes a first end closed by a pierceable membrane, a second end closed by a piston having a first coupling element, and a solvent stored between the membrane and piston;

detachably coupling the first coupling element to a second coupling element on the piston rod, such that the piston follows movement of the piston rod in both axial directions;

ejecting the solvent from the ampoule using the dose setting and injection mechanism;

mixing the ejected solvent with a medicament; and

sucking the mixed solvent and medicament back into the ampoule by actuating the release mechanism and moving the piston rod in a proximal direction.

6. A method according to claim 5, wherein the first and second coupling elements are threads and the coupling step is performed by screwing the coupling elements together.