AUTOMATIC INJECTOR WITH KICKBACK ATTENUATION

• US 20080051715A1
• Filed: 10/25/2007
• Published: 02/28/2008
• Est. Priority Date: 08/06/2004
• Status: Active Grant

• Current Assignee: Mylan Specialty L.P. (Pfizer Inc.)
• Original Assignee: Meridian Medical Technologies Incorporated
• Inventors: Hill, Robert, Young, Matthew, Wilmot, John, Murphy, Martin, Daintrey, Joseph, Rochford, Craig, Raven, Sophie, Hurlstone, Christopher, Kirkwood, Stephen, Mathews, Colin
• Granted Patent: US 7,794,432 B2
• Time in Patent Office: Days
• US Class Current: 604/135
• CPC Class Codes: A61M 2005/2013 triggering of discharging means by contact of injector with patient body
• CPC Class Codes: A61M 2005/206 With automatic needle insertion
• CPC Class Codes: A61M 2005/2073 preventing premature release, e.g. by making use of a safety lock
• CPC Class Codes: A61M 2005/3126 Specific display means related to dosing
• CPC Class Codes: A61M 2005/3247 Means to impede repositioning of protection sleeve from needle covering to needle uncovering position
• CPC Class Codes: A61M 2205/586 Ergonomic details therefor, e.g. specific ergonomics for left or right-handed users
• CPC Class Codes: A61M 5/2033 Spring-loaded one-shot injectors with or without automatic needle insertion multishot dosing syringes A61M5/31525, needle insertion only A61M5/3287
• CPC Class Codes: A61M 5/2459 upon internal pressure increase, e.g. pierced or burst A61M5/2429 takes precedence
• CPC Class Codes: A61M 5/3129 Syringe barrels A61M5/3205 and A61M5/50 take precedence
• CPC Class Codes: A61M 5/31596 comprising means for injection of two or more media, e.g. by mixing
• CPC Class Codes: A61M 5/3245 Constructional features thereof, e.g. to improve manipulation or functioning
• CPC Class Codes: A61M 5/326 Fully automatic sleeve extension, i.e. in which triggering of the sleeve does not require a deliberate action by the user
• CPC Class Codes: A61M 5/3271 with guiding tracks for controlled sliding of needle protective sleeve from needle exposing to needle covering position

Abstract

An auto-injector for dispensing a predetermined dose of medicament is disclosed. The auto-injector includes a needle cover operative to engage an injection site. The needle cover is configured to move from a retracted position prior to a medicament dispensing operation to an extended locked position after the medicament dispensing operation. Any residual activation force remaining after the medicament dispensing operation is contained within the auto-injector and is not directed to the needle cover, thus attenuating, if not eliminating, any kickback effect.

Claims

1. An auto-injector comprising:

a housing having a retention step formed on an inner surface of the housing;

a cartridge having an opening therein and containing a medicament, the medicament rearwardly confined by a plunger received through the opening, the cartridge including a needle assembly operative to dispense the medicament there through during a medicament dispensing operation, the needle assembly including a needle;

a cartridge container disposed within the housing and operative to receive the cartridge therein, the cartridge container having a ledge that abuts the retention step of the housing to limit movement of the cartridge container within the housing, the cartridge container having a closed front end except for an opening therein sized to receive the needle there through during a medicament dispensing operation, the closed front end operative to engage the cartridge and oppose continued movement of the cartridge after the needle passes through the front end opening;

an actuation assembly providing a stored energy source capable of driving the plunger within the cartridge to dispense the medicament through the needle assembly, the actuation assembly secured to the housing; and

a needle cover at least partially received within the housing and positioned between the housing and the cartridge container, the needle cover having an opening formed therein sized to receive the needle there through during a medicament dispensing operation, the needle cover having a first locked retracted position and a second locked extended position, the needle cover extending beyond the housing in the first locked retracted position;

whereby;

energy released from the stored energy source to drive the needle and cartridge during the medicament dispensing operation is not transmitted to the needle cover.

2. The auto-injector of claim 1 wherein the needle cover has a surface operative to contact an injection site prior to a medicament dispensing operation, the surface having the opening to receive the needle there through during a medicament dispensing operation.

3. The auto-injector of claim 1 wherein the actuation assembly is secured to the housing via projections formed on an outer surface of the actuation assembly that are snap fit into respective openings in the housing.

4. The auto-injector of claim 1 further comprising a needle cover spring positioned inside the needle cover between an end surface of the needle cover and the front end of the cartridge container.

5. The auto-injector of claim 4 wherein the front end of the cartridge container is tapered, the cartridge container comprising a plurality of ribs formed on the outer surface of the tapered front end, the needle cover spring disposed about the plurality of ribs.

6. The auto-injector of claim 1 wherein the cartridge further comprises a needle sheath disposed about the needle, the needle sheath being compressed between the cartridge container and the cartridge during the medicament dispensing operation.

7. The auto-injector of claim 1 further comprising a locking mechanism for selectively holding the needle cover in the first locked position and in the second locked position, the locking mechanism located within the housing to protect against tampering and dirt ingress.

8. The auto-injector of claim 1 wherein the stored energy source is a spring.

9. The auto-injector of claim 1 wherein the ledge of the cartridge container is located on an end opposite the closed front end.

10. An auto-injector comprising:

a housing;

a cartridge having an opening therein and containing a medicament, the medicament rearwardly confined by a plunger received through the opening, the cartridge including a needle assembly operative to dispense the medicament there through during a medicament dispensing operation, the needle assembly including a needle;

a cartridge container disposed within the housing and operative to receive the cartridge therein, the cartridge container having an annular structure that engages an inner surface of the housing to limit movement of the cartridge container within the housing, the cartridge container having a closed front end except for an opening therein sized to receive the needle there through during the medicament dispensing operation, the closed front end operative to engage the cartridge and oppose continued movement of the cartridge after the needle passes through the front end opening;

an actuation assembly providing a stored energy source capable of driving the plunger within the cartridge to dispense the medicament through the needle assembly, the actuation assembly secured to the housing; and

a needle cover at least partially received within the housing and operative to receive therein at least the front end of the cartridge container, the needle cover having an opening formed therein sized to receive the needle there through during the medicament dispensing operation, the needle cover having a first locked retracted position and a second locked extended position, the needle cover having a surface operative to contact an injection site prior to a medicament dispensing operation, the surface having the opening to receive the needle there through;

whereby;

residual force from the energy source after activation of the medicament dispensing operation is contained by the cartridge container, the cartridge, the housing, and the actuation assembly to prevent kickback of the auto-injector during the dispensing operation.

11. The auto-injector of claim 10 wherein the annular structure of the cartridge container is a ledge located on an end opposite the closed front end.

12. The auto-injector of claim 10 wherein the needle cover extends beyond the housing in the first locked retracted position.

13. The auto-injector of claim 10 wherein the actuation assembly is secured to the housing via projections formed on an outer surface of the actuation assembly that are snap fit into respective openings in the housing.

14. The auto-injector of claim 10 further comprising a needle cover spring positioned inside the needle cover between an end surface of the needle cover and the front end of the cartridge container.

15. The auto-injector of claim 14 wherein the front end of the cartridge container is tapered, the cartridge container comprising a plurality of ribs formed on the outer surface of the tapered front end, the needle cover spring disposed about the plurality of ribs.

16. The auto-injector of claim 10 wherein the cartridge further comprises a needle sheath disposed about the needle, the needle sheath being compressed between the cartridge container and the cartridge during a medicament dispensing operation.

17. The auto-injector of claim 10 further comprising a locking mechanism for selectively holding the needle cover in the first locked position and in the second locked position, the locking mechanism located within the housing to protect against tampering and dirt ingress.

18. The auto-injector of claim 10 wherein the stored energy source is a spring.