Gas pressured needle-less injection device and method

• US 5,730,723 A
• Filed: 09/25/1996
• Issued: 03/24/1998
• Est. Priority Date: 10/10/1995
• Status: Expired due to Fees

• Current Assignee: PenJet Corp.
• Original Assignee: Visionary Medical Systems Incorporated (CompuGroup Medical SE & Co. KGaA)
• Inventors: Schumecher, Robert, Castellano, Thomas P.
• Primary Examiner(s): Buiz, Michael Powell
• Assistant Examiner(s): NGUYEN, ANH TUAN TUONG
• Application Number:
  US08/719,459
• Time in Patent Office: 545 Days
• Field of Search: 604/68, 604/70, 604/72, 604/110, 604/143, 604/146, 604/148, 222/389
• US Class Current: 604/68
• CPC Class Codes: A61M 2005/2013 triggering of discharging means by contact of injector with patient body
• CPC Class Codes: A61M 2005/2073 preventing premature release, e.g. by making use of a safety lock
• CPC Class Codes: A61M 2005/2418 comprising means for damping shocks on ampoule
• CPC Class Codes: A61M 2005/3104 Caps for syringes without needle
• CPC Class Codes: A61M 2005/3118 via the distal end of a syringe, i.e. syringe end for mounting a needle cannula
• CPC Class Codes: A61M 2005/3123 having air entrapping or venting means, e.g. purging channels in pistons
• CPC Class Codes: A61M 2005/31516 reducing dead-space in the syringe barrel after delivery
• CPC Class Codes: A61M 5/2046 Media being expelled from injector by gas generation, e.g. explosive charge
• CPC Class Codes: A61M 5/2053 Media being expelled from injector by pressurised fluid or vacuum for infusion A61M5/145, A61M5/155
• CPC Class Codes: A61M 5/286 upon internal pressure increase, e.g. pierced or burst A61M5/283 takes precedence
• CPC Class Codes: A61M 5/30 Syringes for injection by jet action, without needle, e.g. for use with replaceable ampoules or carpules
• CPC Class Codes: A61M 5/3007 with specially designed jet passages at the injector's distal end
• CPC Class Codes: A61M 5/3129 Syringe barrels A61M5/3205 and A61M5/50 take precedence
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence
• CPC Class Codes: A61M 5/31525 Dosing burettes, pipettes B01L3/02
• CPC Class Codes: A61M 5/31533 Dosing mechanisms, i.e. setting a dose administrating mechanisms A61M5/31565
• CPC Class Codes: A61M 5/31535 Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose

Abstract

An improved medication delivery device is a pen sized instrument that is powered by compressed inert gas. The needle-less injector device contains pre-filled and pre-measured medication dosages. The injector device has a pre-filled and self-contained compressed gas for providing pressure to inject the medication into the skin surface without the use of a needle. The injector device has a pressure sensitive deployment mechanism which insures proper seating of the injector face against the skin surface before medication delivery is accomplished. The needle-less injector device assures safe use by inexperienced operators (including children) under adverse conditions.

Claims

1. A pre-filled compressed gas activated needle-less injector device suitable for injecting pre-filled liquid medication through the skin surface, the device comprising:

a main body having a first gas chamber, a second gas chamber and a passageway in gaseous communication with the first and the second chambers, wherein the first gas chamber contains a pre-filled compressed gas that exits through the passageway and into the second chamber;

a valve detachably mounted to block the passageway to prevent the flow of the compressed gas from the first gas chamber into the second chamber until detached;

a chamber housing coupled to the main body, the chamber housing comprising;

a liquid chamber that holds the liquid medication;

a liquid forcing assembly disposed within the liquid chamber that forces the liquid medication out from the liquid chamber; and

an orifice formed in one end of the chamber housing and in fluid communication with the liquid chamber, wherein when the valve is permanently detached from blocking the passageway, the compressed gas is released from the first gas chamber into the second gas chamber and the compressed gas pushes the liquid forcing assembly which in turn pushes the liquid medication exits through the orifice and pierces the skin surface; and

an actuating member mounted on the main body to permanently detach the valve to release the compressed gas when a predetermined pressure is applied to the actuating member.

2. A needle-less injector device according to claim 1, further including a coil spring positioned between the actuating member and the main body to bias the actuating member in an un-depressed state, wherein the coil spring has sufficient tension so that the predetermined pressure to activate the actuating member is established when the orifice is positioned substantially perpendicular to the skin surface.

3. A needle-less injector device according to claim 1, further including a lever slidably mounted through a side wall of the main body adjacent to the valve and triggered by the actuating member so that when one end of the lever is pushed in, the other end of the lever permanently detaches the valve from blocking the passageway thus releasing the compressed gas into the second gas chamber.

4. A one-time use, pre-filled compressed gas activated needle-less injector device suitable for injecting pre-filled liquid medication through the skin surface, the device comprising:

a main body having a first gas chamber, a second gas chamber and a passageway in gaseous communication with the first and the second chambers, wherein the first gas chamber contains a pre-filled compressed gas that exits through the passageway and into the second chamber;

a valve detachably mounted to block the passageway to prevent the flow of the compressed gas from the first gas chamber into the second chamber until detached;

a chamber housing coupled to the main body, the chamber housing comprising;

a liquid chamber that holds the liquid medication;

a piston disposed and movable within the liquid chamber, wherein the piston includes a head disposed within the main body and creates an air and fluid tight seal so that compressed gas released from the first gas chamber is trapped in the second gas chamber;

a plunger disposed and movable within the liquid chamber along with the piston to force the liquid medication out from the liquid chamber; and

an orifice formed in one end of the chamber housing and in fluid communication with the liquid chamber, wherein when the valve is permanently detached from blocking the passageway, the compressed gas is released from the first gas chamber into the second chamber and the compressed gas pushes the piston which in turn pushes the plunger with the piston so that the liquid medication exits through the orifice and pierces the skin surface;

an actuating member mounted on the main body to permanently detach the valve to release the compressed gas when a predetermined pressure is applied to the actuating member;

a coil spring positioned between the actuating member and the main body to bias the actuating member in an un-depressed state, wherein the coil spring has sufficient tension so that the predetermined pressure to activate the actuating member is established when the orifice is positioned substantially perpendicular to the skin surface; and

a lever slidably mounted through a side wall of the main body adjacent to the valve and triggered by the actuating member so that when one end of the lever is pushed in, the other end of the lever permanently detaches the valve from blocking the passageway thus releasing the compressed gas into the second gas chamber.

5. A method for constructing a pre-filled compressed gas activated needle-less injector device suitable for injecting pre-filled liquid medication through the skin surface, the method comprising the steps of:

forming a main body having a first gas chamber, a second gas chamber and a passageway in gaseous communication with the first and the second chambers, wherein gases in the first gas chamber exit through the passageway and into the second chamber;

detachably mounting a valve to block the passageway to prevent the flow of the compressed gas from the first gas chamber into the second chamber until detached;

forming a chamber housing by the steps of;

forming a liquid chamber that holds the liquid medication,

forming a liquid forcing assembly disposed within the liquid chamber that forces the liquid medication out from the liquid chamber, and

forming an orifice formed in one end of the chamber housing and in fluid communication with the liquid chamber, wherein when the valve is permanently detached from blocking the passageway the compressed gas is released from the first gas chamber and the compressed gas pushes the liquid forcing assembly which in turn pushes the liquid medication out through the orifice and through the skin surface;

coupling the chamber housing to the main body;

mounting an actuating member on the main body to permanently detach the valve to release the compressed gas when a predetermined pressure is applied to the actuating member;

disposing a coil spring between the actuating member and the main body to bias the actuating member away from the main body, wherein the coil spring has a sufficient tension so that the predetermined pressure is established to activate the actuating member when the orifice is positioned substantially perpendicular to the skin surface;

filling the first gas chamber with compressed gas;

filling the liquid chamber with liquid medication; and

slidably mounting a lever through a side wall of the main body adjacent to the valve so that when one end of the lever is pushed in by the actuating member, the other end of the lever permanently detaches the valve from blocking the passageway thus releasing the compressed gas into the second gas chamber.

6. A method according to claim 5 wherein the step of forming the liquid forcing assembly includes the steps of:

installing a piston movable within the liquid chamber, wherein the piston includes a head disposed within the main body and creates an air and fluid tight seal to define the second gas chamber so that compressed gas released from the first gas chamber is trapped in the second gas chamber; and

installing a plunger movable within the liquid chamber along with the piston to force the liquid medication out from the liquid chamber.