Seal structures for wet/dry automatic injectors

• US 20070142769A1
• Filed: 01/26/2007
• Published: 06/21/2007
• Est. Priority Date: 10/10/2000
• Status: Active Grant

• Current Assignee: Meridian Medical Technologies Incorporated
• Original Assignee: Meridian Medical Technologies Incorporated
• Inventors: Hill, Robert, Griffiths, Steven
• Granted Patent: US 7,749,190 B2
• Time in Patent Office: Days
• US Class Current: 604/82
• 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 2005/287 by displacing occluding plugs
• CPC Class Codes: A61M 2005/3106 Plugs for syringes without needle
• CPC Class Codes: A61M 2005/3131 specially adapted for improving sealing or sliding
• CPC Class Codes: A61M 2005/3132 having flow passages for injection agents at the distal end of the barrel to bypass a sealing stopper after its displacement to this end due to internal pressure increase
• CPC Class Codes: A61M 2202/064 Powder
• CPC Class Codes: A61M 2205/7536 allowing gas passage, but preventing liquid passage, e.g. liquophobic, hydrophobic, water-repellent membranes
• CPC Class Codes: A61M 2205/7545 for solid matter, e.g. microaggregates
• CPC Class Codes: A61M 5/19 having more than one chamber , e.g. including a manifold coupling two parallelly aligned syringes through separate channels to a common discharge assembly surgical glue applicators A61B17/00491
• 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 5/2066 comprising means for injection of two or more media, e.g. by mixing
• CPC Class Codes: A61M 5/284 comprising means for injection of two or more media, e.g. by mixing
• CPC Class Codes: A61M 5/286 upon internal pressure increase, e.g. pierced or burst A61M5/283 takes precedence
• CPC Class Codes: A61M 5/3145 Filters incorporated in syringes
• CPC Class Codes: A61M 5/31513 Piston constructions to improve sealing or sliding
• CPC Class Codes: A61M 5/31596 comprising means for injection of two or more media, e.g. by mixing
• 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
• CPC Class Codes: A61M 5/3293 characterised by features of the needle hub
• CPC Class Codes: A61M 5/34 Constructions for connecting the needle , e.g. to syringe nozzle or needle hub connecting catheter tubes to hubs A61M25/0014
• CPC Class Codes: A61M 5/343 : Connection of needle cannula to needle hub, or directly to syringe nozzle without a needle hub A61M5/322 takes precedence
• CPC Class Codes: A61M 5/348 : snap lock, i.e. upon axial displacement of needle assembly A61M5/344 takes precedence

Abstract

An automatic medicament injector having a compartment for a dry medicament component and a compartment for a wet medicament component. The two compartments are separated by a seal structure that converts from a sealing condition to a mixing condition when the device is activated. The seal structure includes a wiper that scrapes the interior walls in the dry component compartment to prevent the dry component from accumulating at the seal/glass interface. A tapered insert funnels the mixed medicament components to an attached needle assembly, but can be removed when the device is filled. A filter is provided between the medicament compartments and the needle assembly. A chamber between the filter and the needle allows for better flow through the filter. An actuation assembly drives the seal structure into the mixing condition and forces the mixed medicament through the needle and into the user.

Claims

1. An automatic injection device containing a pre-loaded charge of medicament for automatically self-administering the medicament upon actuation thereof, the device comprising:

a housing;

a medicament chamber disposed in the housing, the medicament chamber including a first compartment containing a dry medicament portion, and a second compartment containing a wet medicament portion to be mixed with the dry medicament portion;

a seal structure between the first compartment and the second compartment, the seal structure being initially in a sealing condition that maintains the first compartment separate from the second compartment, the seal structure including;

at least one flow path formed therein, and

an annular wiper portion disposed at the front end of the seal structure and positioned to engage inner walls of the first compartment as the seal structure is moved through said first compartment, said wiper portion being configured to direct dry medicament particles engaged with the inner walls radially inwardly as the seal structure moves through the first compartment, the seal structure being converted to a mixing condition as a result of activation of the device;

a needle assembly that dispenses the mixed medicament portions from the medicament chamber; and

an activation assembly carried by the housing and including a stored energy source, wherein activation of the activation assembly releases the stored energy from the stored energy source, causing the seal structure to be converted from the sealing condition to the mixing condition, and thereby causing or allowing the medicament portions to be mixed and forced through the needle assembly.

2. The automatic injection device of claim 1, wherein the first compartment is adjacent the needle assembly and disposed forwardly of the second compartment.

3. The automatic injection device of claim 1, further comprising an insert mounted in the forward end of the chamber adjacent the needle assembly, the insert defining a tapering flow pathway that tapers radially inwardly as it extends axially forward.

4. The automatic injection device of claim 3, further comprising a filter positioned between the medicament chamber and the needle assembly.

5. The automatic injection device of claim 4, wherein the needle assembly comprises a needle support for mounting the needle assembly to a front end of the medicament chamber, the needle support defining a chamber provided adjacent to the filter on a needle assembly side of the filter.

6. The automatic injection device of claim 5, wherein the needle support chamber adjacent to the filter has an enlarged rearward end opening of a size that is at least as large as a front end opening of the insert.

7. The automatic injection device of claim 6, wherein the needle support chamber adjacent to the filter has a substantially hemispherical shape.

8. The automatic injection device of claim 7, further comprising a fluid distributing member disposed between the first compartment and the second compartment.

9. The automatic injection device of claim 8, wherein the fluid distributing member is a filter.

10. The automatic injection device of claim 1, wherein the seal structure comprises an outer seal structure carrying the wiper portion, the flow path being formed in the outer seal structure, and a plug member for sealing the flow path when the seal structure is in the sealing condition.

11. The automatic injection device of claim 10, wherein the seal structure has an outer periphery that forms a peripheral seal with an interior wall of the medicament chamber, and wherein said plug member is spaced radially inward from the peripheral seal that seals the at least one flow path formed in the seal structure.

12. The automatic injection device of claim 1, wherein the wiper portion comprises a peripheral lip having an inner surface that extends radially inwardly as it extends axially rearward.

13. An automatic injection device containing a pre-loaded charge of medicament for automatically administering the medicament upon actuation thereof, the device comprising:

a housing;

a chamber disposed in the housing, the chamber having a first compartment containing a dry medicament portion, and a second compartment containing a wet medicament portion to be mixed with the dry medicament portion;

a seal structure between the first compartment and the second compartment, the seal structure initially in a sealed condition to maintain the first compartment separate from the second compartment, the seal structure converting to a mixing condition in response to activation of the device, the seal structure including;

an outer sealing member that forms a peripheral seal with an interior wall of the chamber,

a movable sealing plug spaced radially inward from the outer sealing member, the sealing plug in a first position when the seal structure is in the sealed condition and in a second position when the seal structure is in the mixing condition,

a filter or dispersion membrane, and

at least one flow path between the sealing plug and the dispersion membrane;

a needle assembly that dispenses the mixed medicament portions from the chamber; and

an activation assembly disposed in the housing and including a stored energy source, wherein activation of the activation assembly releases the stored energy from the stored energy source causing the seal structure to convert from the sealed condition to the mixing condition, wherein the medicament portions are mixed and forced through the needle assembly.

14. The automatic injection device of claim 13, wherein the seal structure further comprises an annular wiper portion disposed at the front end of the outer sealing member, the wiper portion positioned to engage an interior wall of the first compartment as the seal structure is moved through the first compartment, the wiper portion configured to direct dry medicament particles engaged with the interior wall radially inward as the seal structure moves through the first compartment when in the mixing condition.

15. The automatic injection device of claim 14, wherein the annular wiper portion comprises a peripheral lip having an inner surface that extends radially inward as it extends axially rearward.

16. The automatic injection device of claim 13, wherein the outer sealing member comprises an O-ring that provides an annular seal with the interior wall of the chamber.

17. The automatic injection device of claim 13, wherein the seal structure further comprises a by-pass zone between the movable plug in the sealed condition and the dispersion filter or membrane.

18. The automatic injection device of claim 13, wherein the dispersion filter or membrane comprises a hydrophobic acrylic copolymer cast on a non-woven nylon support.

19. An automatic injection device containing a pre-loaded charge of medicament for automatically administering the medicament upon actuation thereof, the device comprising:

a housing;

a chamber disposed in the housing, the chamber having a first compartment containing a dry medicament portion, and a second compartment containing a wet medicament portion to be mixed with the dry medicament portion;

a seal structure between the first compartment and the second compartment, the seal structure initially in a sealed condition to maintain the first compartment separate from the second compartment, the seal structure including;

an outer sealing member that forms a peripheral seal with an interior wall of the chamber,

a seal membrane extending across the inner area defined by the inner surface of the outer sealing member, the seal membrane operative to rupture upon pressurization of the second compartment,

a dispersion filter or membrane, and

at least one flow path between the seal and dispersion membranes;

a needle assembly that dispenses the mixed medicament portions from the chamber; and

an activation assembly disposed in the housing and including a stored energy source, wherein activation of the activation assembly releases the stored energy from the stored energy source causing the second compartment to pressurize and the seal membrane to rupture, wherein the medicament portions are mixed and forced through the needle assembly.

20. The automatic injection device of claim 19, wherein the seal structure further comprises a pointed member disposed adjacent the seal membrane to facilitate rupturing of the seal membrane upon pressurization of the second compartment.