DRUG DELIVERY DEVICE

• US 20120083748A1
• Filed: 03/31/2010
• Published: 04/05/2012
• Est. Priority Date: 03/31/2009
• Status: Active Grant

• Current Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Original Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Inventors: Harms, Michael, Dasbach, Uwe, Raab, Steffen, Korger, Volker
• Granted Patent: US 9,555,194 B2
• Time in Patent Office: Days
• US Class Current: 604/224
• CPC Class Codes: A61M 2005/3115 spring-assisted
• CPC Class Codes: A61M 5/178 Syringes
• CPC Class Codes: A61M 5/315 Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
• CPC Class Codes: A61M 5/31525 Dosing burettes, pipettes B01L3/02
• 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

Abstract

A mechanism in the body is used to drive a piston rod and comprises means for guiding the movement of the piston rod relatively to the body while delivering the drug. Further means are provided for releasing the piston rod from the means for guiding the movement, thus enabling a reset of the piston rod to a start position, especially after the receptacle has been emptied and is to be refilled. The device is constructed in such a manner that a reset of the piston rod is facilitated by a stop element inhibiting a reversal of the movement of the piston rod when being reset.

Claims

1. A drug delivery device, comprising:

a body having a receptacle for a drug;

a piston rod (8) in the body, the piston rod being movable relatively to the body and being provided for expelling the drug out of the receptacle;

a mechanism provided to drive the piston rod while delivering the drug, the piston rod having a start position with respect to the mechanism;

a device for guiding the movement of the piston rod relatively to the body while delivering the drug;

a device for releasing the piston rod from the device for guiding the movement, the device for releasing being provided to enable a reset of the piston rod to the start position; and

a stop element provided for inhibiting a movement of the piston rod away from the start position, when the piston rod has been released.

2. The drug delivery device according to claim 1, wherein the stop element is engaged with the body in such a manner that a rotation of the stop element relatively to the body is inhibited.

3. The drug delivery device according to claim 1, further comprising:

a groove in the body, the groove guiding the stop element; and

a stop of the groove provided for blocking a movement of the stop element opposite to the movement of the piston rod during reset.

4. The drug delivery device according to claim 1, wherein the device for guiding the movement of the piston rod provided to engage the piston rod with the stop element if a movement of the piston rod away from the start position occurs when the piston rod has been released.

5. The drug delivery device according to claim 1, further comprising:

the device for guiding the movement of the piston rod comprising a piston rod nut;

a device for fixing the piston rod nut relatively to the body;

the device for releasing the piston rod comprising a spring provided for releasing the piston rod nut from being fixed relatively to the body.

6. The drug delivery device according to claim 5, further comprising:

the device for fixing the piston rod nut relatively to the body comprising a lock nut;

the lock nut being the stop element;

a device for inhibiting a rotation of the lock nut relatively to the body;

a device for fixing the piston rod nut relatively to the lock nut; and

the spring being arranged at the lock nut in such a manner as to make the spring tend to release the lock nut from the device that is provided for fixing the piston rod nut relatively to the lock nut.

7. The drug delivery device according to claim 5, wherein the piston rod and the piston rod nut are formed from synthetic or plastic materials that have a value of the coefficient μ

of sliding friction of at most 0.25 at a relative velocity of the sliding surfaces of 2 mm per second.

8. The drug delivery device according to claim 5, wherein the piston rod nut is arranged in contact with the body;

and the body and the piston rod nut are formed from synthetic or plastic materials that have a value of the coefficient μ

of sliding friction of at most 0.25 at a relative velocity of the sliding surfaces of 2 mm per second.

9. The drug delivery device according to claim 5, further comprising:

the piston rod comprising a screw thread;

the piston rod nut comprising a thread corresponding to the screw thread of the piston rod and engaging the screw thread of the piston rod; and

the piston rod having an axis, a tangent of a helix formed by the screw thread of the piston rod making an angle of at least 25°

with the axis.

10. The drug delivery device according to claim 9, further comprising:

a further screw thread of the piston rod;

the piston rod having an axis, a tangent of a helix formed by the further screw thread of the piston rod making an angle of at least 40°

with the axis;

the mechanism comprising a drive sleeve having a thread corresponding to the further screw thread of the piston rod and engaging the further screw thread of the piston rod; and

the reset of the piston rod to the start position comprising a helical movement of the piston rod relatively to the drive sleeve according to the further screw thread of the piston rod.

11. The drug delivery device according to claim 10, wherein the piston rod are formed from synthetic or plastic materials that have a value of the coefficient μ

of sliding friction of at most 0.25 at a relative velocity of the sliding surfaces of 2 mm per second.

12. The drug delivery device according to claim 7, wherein the synthetic or plastic materials are provided with surfaces having centre line averages, measuring a roughness, of less than 1.6 μ

m.

13. The drug delivery device according to claim 1, wherein the receptacle is provided for inserting a cartridge.

14. The drug delivery device according to claim 13, wherein the cartridge bars the stop element.

15. The drug delivery device according to claim 13, wherein the cartridge contains a drug.

16. The drug delivery device according to claim 1, wherein the piston rod has a weight, which resets the piston rod by a gravitational force when the piston rod is released and the drug delivery device is directed in such a manner as to make the gravitational force drive the piston rod towards the start position.