Prefilled drug delivery device with reduced air gap
AssigneeNovo Nordisk A/S
InventorsDaniel Knudsen, Jeppe Marckmann
Life of this patent
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Abstract
A method of assembling a drug delivery device, comprising the steps of: inserting a piston rod in a nut portion of a cartridge assembly and rotating the piston rod until the piston rod distal end engages the cartridge piston, mounting a drive member on the piston rod in a rota-tional position being closest to a pre-determined rotational position, and rotating the drive member to the pre-determined rotational position.
Claims15
A method of assembling a cartridge-piston rod sub-assembly for a drug delivery device, comprising the steps of:
- (i) providing an assembly comprising:
- a cartridge with an axially displaceable piston, the piston comprising a proximally facing free surface,
- a cartridge holder in which the cartridge is arranged, and
- a nut portion arranged proximally of the piston and comprising a threaded bore,
- (ii) providing a threaded piston rod comprising at least one outer drive structure and a distal end,
- (iii) providing a drive member comprising at least one inner drive structure, the number and circumferential spacing of the outer and inner drive structures allowing the piston rod to be axially received in at least three different rotational positions in which the piston rod and drive member are in axially sliding but rotationally locked engagement, the drive member having at least one pre-determined rotational position relative to the cartridge holder,
- (iv) inserting the piston rod in the nut portion threaded bore and rotating the piston rod until the piston rod distal end engages, directly or indirectly, the cartridge piston,
- (v) mounting the drive member on the piston rod in the rotational position being closest to a pre-determined rotational position, and
- (vi) rotating the drive member to the pre-determined rotational position.
The method of assembling as in clam 1, wherein in step (iv) the drive member is rotated to retract the piston rod when rotated to a pre-determined rotational position.
A drug delivery device comprising:
- a cartridge comprising a cylindrical body portion defining an axial orientation, an outlet portion and an axially displaceable piston,
- a housing,
- an expelling arrangement comprising:
- a piston rod adapted to engage and axially displace, directly or indirectly, the cartridge piston in a distal direction to thereby expel a dose of drug from the cartridge, the piston rod comprising:
- an outer thread, and
- at least one outer drive structure,
- a nut portion non-rotationally coupled to the housing and comprising a threaded bore receiving the piston rod in threaded engagement,
- a drive member in which the piston rod is arranged, comprising at least one inner drive structure, the number and circumferential spacing of the outer and inner drive structures allowing the piston rod to be mounted in at least three different rotational positions in which the piston rod and drive member are in axially sliding but rotationally locked engagement, and
- a drive arrangement allowing a user to rotate the drive member to thereby expel an amount of drug from the cartridge as the piston rod is rotated and moved axially through the nut portion.
A cartridge-piston rod sub-assembly for a drug delivery device, comprising:
- a cartridge with an axially displaceable piston, the piston comprising a proximally facing free surface,
- a cartridge holder in which the cartridge is arranged,
- a nut portion non-rotationally coupled to the cartridge holder and comprising a threaded bore adapted to receive the piston rod in threaded engagement,
- a piston rod received in the threaded bore and adapted to engage and axially displace, directly or indirectly, the cartridge piston in a distal direction to thereby expel a dose of drug from the cartridge, the piston rod comprising:
- an outer thread, and
- at least one outer drive structure,
- a drive member in which the piston rod is arranged, comprising at least one inner drive structure, the number and circumferential spacing of the outer and inner drive structures allowing the piston rod to be mounted in at least three different rotational positions in which the piston rod and drive member are in axially sliding but rotationally locked engagement.
Dependencies are inferred from the claim text.