Reusable engine for an auto-injector

Patent metadata

Field	Value
Publication number	US-9623183-B2
Application number	US-201113876167-A
Country	US
Kind code	B2
Filing date	Oct 6, 2011
Priority date	Oct 8, 2010
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

An engine for an-auto injector for administering a dose of a liquid medicament includes a case arranged to be attached to a package syringe containing a syringe. The case contains a drive capable of, upon activation, pushing the needle from a covered position into an exposed position, and operating the syringe to supply the dose of medicament. The case contains a trigger arranged to lock the drive in a loaded state prior to manual operation and capable of, upon manual operation, releasing the drive for injections. The drive is arranged as a gas spring including a cylinder and a piston with a plunger for transmitting the spring force. A latch is arranged for preventing translating between the cylinder and the case. The latch is disengageable by the released gas spring being at least nearly fully extended thus allowing the extended gas spring to be translated in a distal direction.

First claim

The invention claimed is:

1. An engine for an auto-injector for administering a dose of a liquid medicament, the engine comprising:
a case having a distal end and a proximal end arranged to be attached to a packaged syringe containing a syringe with a hollow needle and a stopper for sealing the syringe and displacing the medicament, wherein the syringe is slidably arranged with respect to the case, the case containing
a drive arranged to, upon activation, push the needle from a covered position into an exposed position, and operate the syringe to supply the dose of medicament, and
a trigger arranged to lock the drive in a loaded state prior to manual operation and, upon manual operation, to release the drive for injection,

wherein the drive is arranged as a gas spring comprising a cylinder and a piston with a plunger for transmitting a force of the gas spring,
wherein a compressed gas is provided in a high pressure cavity defined between the piston and a distal end of the cylinder,
wherein the cylinder is slidably arranged in the case, and
wherein a latch is arranged to inhibit translation between the cylinder and the case and to be disengaged by the gas spring in a released state being at least nearly fully extended thus allowing the gas spring in an extended state to be translated in a distal direction.

2. The engine according to claim 1 , further comprising a cylinder spring arranged in the case for biasing the cylinder against the case in the distal direction.

3. The engine according to claim 1 , wherein the compressed gas is Nitrogen.

4. The engine according to claim 1 , wherein the compressed gas exhibits a pressure of approximately 10 bar when the gas spring is in the loaded state.

5. The engine according to claim 1 , wherein the trigger is arranged as a trigger button laterally arranged at the case, the trigger button having a dog for engaging the plunger prior to manual operation to inhibit translation of the plunger, wherein the dog is arranged to disengage from the plunger upon manual operation.

6. The engine according to claim 5 , wherein the dog is shaped as a loop with an aperture for the plunger, wherein the aperture comprises a narrow portion aligned with the plunger prior to manual operation of the trigger button and a wide portion aligned with the plunger upon manual operation, wherein the plunger has a main section and a locking section, the main section being hidden in the cylinder and the locking section outside the cylinder when the gas spring is in the loaded state, wherein the narrow portion has a diameter smaller than a diameter of the main section but wider than a diameter of the locking section, wherein the wide portion has a diameter at least as wide as the diameter of the main section, wherein the locking section is engaged with the narrow portion prior to manual operation.

7. The engine according to claim 6 , wherein beyond the locking section in a proximal direction the plunger comprises a shoulder followed by a pin with the shoulder having a greater diameter than the pin, wherein a plunger front part is telescoped with the pin, wherein a plunger spring is arranged on the pin to bias the plunger front part against the pin.

8. The engine according to claim 5 , wherein a second latch is arranged in the case, the second latch slidable between a locking position obstructing the trigger button to inhibit the trigger button from being pressed and an unlocked position allowing the trigger button to be pressed inwardly.

9. The engine according to claim 8 , wherein the second latch is arranged to be pushed into the unlocked position by a transfer sleeve arranged in the packaged syringe when a proximal end of the transfer sleeve is pushed against an injection site.

10. The engine according to claim 1 , further comprising a valve arranged in the cylinder to restrict venting of a low pressure side of the piston opposite the high pressure cavity.

11. The engine according to claim 10 , wherein the valve is arranged to maintain a damping rate greater than a damping force generated due to friction between the stopper and an inner wall of the syringe and due to hydraulic resistance of the liquid medicament forced through the hollow needle.

12. An auto-injector for administering a dose of a liquid medicament, the auto-injector comprising:
a packaged syringe comprising a syringe with a hollow injection needle and a stopper for sealing the syringe and displacing the liquid medicament; and
an engine comprising
a case having a distal end and a proximal end arranged to be attached to the packaged syringe, wherein the syringe of the packaged syringe is slidably arranged with respect to the case, the case containing
a drive arranged, upon activation, to push the needle from a covered position into an exposed position, and to operate the syringe to supply the dose of medicament, and
a trigger arranged to lock the drive in a loaded state prior to manual operation and, upon manual operation, to release the drive for injection,

wherein the drive is arranged as a gas spring comprising a cylinder and a piston with a plunger for transmitting a force of the gas spring,
wherein a compressed gas is provided in a high pressure cavity defined between the piston and a distal end of the cylinder,
wherein the cylinder is slidably arranged in the case,
wherein a latch is arranged to inhibit translation between the cylinder and the case and to be disengaged by the gas spring in a released state being at least nearly fully extended thus allowing the gas spring in an extended state to be translated in a distal direction,
wherein the syringe is at least partially arranged inside a tubular syringe retainer arranged for connecting the packaged syringe to the engine and for restricting longitudinal motion of the syringe,
wherein the syringe and the needle are hidden inside the packaged syringe when the drive is in the loaded state,
wherein the syringe is biased in the distal direction by a syringe spring and movable in a proximal direction by the drive into a position with the needle protruding beyond a proximal end of the packaged syringe.

13. The auto-injector according to claim 12 , further comprising a tubular transfer sleeve arranged around the syringe to hide the syringe when the drive is in the loaded state, the transfer sleeve biased in the proximal direction and movable in the distal direction when pressed against an injection site, wherein the transfer sleeve extends through the syringe retainer to engage a second latch of the engine.

14. The auto-injector according to claim 12 , further comprising a removable cap arrangeable on the packaged syringe.

15. The auto-injector according to claim 14 , wherein the cap is arranged to engage a protective needle sheath arrangeable on the needle to remove the protective needle sheath upon removal of the cap.

16. The auto-injector according to claim 12 , wherein the trigger is arranged as a trigger button laterally arranged at the case, the trigger button having a dog for engaging the plunger prior to manual operation to inhibit translation of the plunger, wherein the dog is arranged to disengage from the plunger upon manual operation.

17. The auto-injector according to claim 16 , wherein the dog is shaped as a loop with an aperture for the plunger, wherein the aperture comprises a narrow portion aligned with the plunger prior to manual operation of the trigger button and a wide portion aligned with the plunger upon manual operation, wherein the plunger has a main section and a locking section, the main section being hidden in the c

Assignees

• Jennings Douglas
• Kemp Thomas
• Ekman Matthew
• Sanofi Aventis Deutschland

Inventors

• Jennings Douglas
• Kemp Thomas
• Ekman Matthew

Classifications

• A61M5/2053 Primary

  Media being expelled from injector by pressurised fluid or vacuum (for infusion A61M5/145, A61M5/155) · CPC title

• A61M2005/206

  With automatic needle insertion · CPC title

• A61M2005/208

  Release is possible only when device is pushed against the skin, e.g. using a trigger which is blocked or inactive when the device is not pushed against the skin · CPC title

• A61M5/3204

  Needle cap remover, i.e. devices to dislodge protection cover from needle or needle hub, e.g. deshielding devices · CPC title

• A61M5/326

  Fully automatic sleeve extension, i.e. in which triggering of the sleeve does not require a deliberate action by the user · CPC title