Details for Patent: 6,565,553

Title:	Needle assisted jet injector
Abstract:	The invention relates to methods and devices for delivering medicament by jet injection to an injection site in a patient. The method includes inserting a needle into an insertion point, wherein the needle has a length of less than 5 mm and is operatively associated with an orifice in a nozzle assembly in fluid communication with an ampule chamber containing the medicament. The needle extends less than about 5 mm from the nozzle assembly orifice when the medicament is expelled. Next, a force generating mechanism is activated, and a pressure wall member that is operatively associated with the force generating member moves in response to the activation of the force generating mechanism at a speed sufficient to jet inject the medicament from the ampule chamber through the orifice and needle under a pressure of less than about 4000 psi to deliver a substantial portion of the medicament through the needle and past the insertion point to the injection site. The needle tip maybe part of a retractable needle of a jet injection device, or is part of a fixed needle of a jet injection device.
Inventor(s):	Sadowski; Peter L. (Woodbury, MN), DeBoer; David M. (Waconia, MN), Berman; Claude L. (St. Paul, MN), Lesch, Jr.; Paul R. (Lexington, MN)
Assignee:	Antares Pharma, Inc. (Minneapolis, MN)
Filing Date:	Jan 31, 2002
Application Number:	10/062,652
Claims:	1. A jet injection device comprising a housing, a retractable injection-assisting needle at a distal end of the injector; a nozzle assembly defining a fluid chamber and having an opening for allowing at least a portion of the needle to pass therethrough, with the nozzle assembly being removably associated with the housing; a plunger movable in the fluid chamber; a trigger assembly; and a force generating source operatively associated with the trigger assembly such that movement of the trigger assembly activates the force generating source to move the plunger in a first direction to expel a fluid from the fluid chamber; with the retractable injection-assisting needle comprising: a needle tip located at a distal end of the needle with at least a portion configured and dimensioned to move through the nozzle assembly opening; a discharge channel within the needle tip and terminating in an orifice through which the fluid is expelled; a body portion to direct fluid towards the discharge channel; a plunger receptor configured and dimensioned to receive at least a portion of the plunger; and a retraction element operatively associated with the needle and disposed substantially within the nozzle assembly; wherein the needle is located within the nozzle assembly in a retracted position prior to activation of the force generating source; movement of the plunger in the first direction upon activation of the force generating source results in extension of at least a portion of the needle tip beyond the nozzle assembly opening to a needle insertion point, with the retraction element returning the needle tip to the retracted position after activation of the force generating source; the needle tip, when extended, has a length sufficient to puncture the epidermis of a patient so that the fluid is delivered to an injection site that is substantially remote from the needle tip. 2. The injection device of claim 1, wherein the retraction element is a resilient O-ring, a spring, or a flexible membrane which moves to allow the needle tip to extend beyond the nozzle assembly opening and then returns the needle to its original position to return the needle tip to its retracted position. 3. The injection device of claim 1, wherein the needle body has an exterior surface which includes a ridge or recess for accommodating the retraction element. 4. The injection device of claim 1, wherein a shoulder is disposed between the needle tip and the needle body for accommodating the retraction element. 5. The injection device of claim 1, wherein the needle tip, when extended, has a length of approximately 1-5 mm. 6. The device of claim 1, wherein the force generating source provides a pressure of less than about 4000 psi to expel the fluid by jet injection through the needle tip and past the needle insertion point to the injection site. 7. A jet injection device comprising a housing; a nozzle assembly removably associated with the housing and defining a fluid chamber; a plunger movable in the fluid chamber of the nozzle assembly; a trigger assembly; a force generating source operatively associated with the trigger assembly such that movement of the trigger assembly activates the force generating source to move the plunger in a first direction to expel a fluid from the fluid chamber; and a fixed, non-retractable injection-assisting needle comprising a needle body fixed to and extending less than about 5 mm from a distal end of the nozzle assembly, and a discharge channel extending through the needle body, in fluid communication at a first end with the fluid chamber, and terminating at a second end in an orifice through which the fluid is expelled at a needle insertion point that is located at a needle tip of the needle, wherein the needle tip has a length sufficient to puncture the epidermis of a patient, and the force generating source provides a force of less than about 40 lbs for moving the plunger to expel the fluid through the needle tip and past the needle insertion point to an injection site that is substantially remote from the needle tip. 8. The injection device of claim 7, wherein when the orifice is located within the epidermis, the fluid is expelled in a jet stream that extends from the orifice to a layer of tissue below the epidermis. 9. The injection device of claim 7, wherein the needle body is affixed to the nozzle assembly by a friction fit, snap-attachment, or ultrasonic bond. 10. The injection device of claim 9, wherein the needle body is affixed to the distal end of the nozzle assembly. 11. The injection device of claim 9, wherein the nozzle assembly includes first and second sections and the first section includes a needle body. 12. A method of delivering medicament by jet injection to an injection site in a patient comprising the steps of: inserting a needle into an insertion point by less than 5 mm and being operatively associated with an orifice in a nozzle assembly in fluid communication with an ampule chamber containing the medicament, the needle extending less than about 5 mm from the nozzle assembly orifice when the medicament is expelled; activating a force generating mechanism; and operatively associating a pressure wall member with the force generating member, with the pressure wall member being disposed and movable within the ampule chamber, so that the force generating member exerts a force of less than 40 lbs on the pressure wall member for moving the pressure wall member at a speed sufficient to jet inject the medicament from the ampule chamber through the orifice and needle to deliver a substantial portion of the medicament through the needle and past the insertion point to the injection site, wherein the needle insertion point is located at the needle tip and the needle injection site is substantially remote from the needle tip. 13. The method of claim 12, wherein the needle tip is part of a retractable needle of a jet injection device. 14. The method of claim 12, further comprising the step of extending a needle from a shield prior to inserting the needle into the needle insertion point, said shield concealing the needle. 15. The method of claim 14, further comprising the step of retracting the needle into the shield after the medicament has been delivered to the injection site. 16. The method of claim 12, wherein the needle tip is part of a fixed needle of a jet injection device. 17. The method of claim 12, wherein the needle insertion point is the epidermis layer of skin and the injection site is the subcutaneous region. 18. A jet injection device, comprising: a housing; a nozzle assembly associated with the housing to define a distal end, the nozzle assembly defining a fluid chamber configured for containing a fluid, and the nozzle assembly comprising an injection-assisting needle configured for penetrating an injection point up to the distal end, the needle defining a discharge channel in fluid communication with the fluid chamber and with a needle orifice of the needle, wherein the needle orifice is disposed beyond but less than about 5 mm from the distal end for delivering the fluid; a pressure wall associated with the fluid chamber for pressurizing the fluid therein; a trigger assembly operable by a user; and a force generating source associated with the trigger assembly such that the operation of the trigger assembly activates the force generating source for providing a force of less than about 40 lbs on the pressure wall to expel the fluid from the fluid chamber through the discharge channel to an injection site that is substantially remote from the orifice. 19. The device of claim 18, wherein the force is between about 20 lbs and 40 lbs. 20. The device of claim 18, further comprising a plunger that comprises the pressure wall. 21. The device of claim 18, wherein the orifice is disposed at a needle tip of the needle. 22. The device of claim 18, wherein the injection-assisting needle is fixed and non-retractable. 23. The device of claim 18, wherein the needle is a retractable with respect to the distal end. 24. The device of claim 18, wherein the needle is configured for insertion into the insertion point, which is on the epidermis layer of skin, with the injection site being in the subcutaneous region. 25. The device of claim 18, wherein the force generating source is configured for providing a pressure of less than about 4000 psi to expel the fluid to the injection site. 26. The device of claim 18, wherein the force generating source is a coil spring. 27. A method of delivering medicament by jet injection to an injection site in a patient comprising the steps of: inserting a needle into an insertion point, the needle being operatively associated with an orifice in a nozzle assembly in fluid communication with an ampule chamber containing the medicament, the needle having a needle orifice located at a distal end of the needle, the needle extending less than about 5 mm from the nozzle assembly orifice when the medicament is expelled; activating a force generating mechanism that is; and operatively associated with a pressure wall member, the pressure wall member being disposed and movable within the ampule chamber, so that the pressure wall member moves in response to the activation of the force generating mechanism at a speed sufficient to jet inject the medicament from the ampule chamber through the orifice and needle under a pressure of less than about 4000 psi to deliver a substantial portion of the medicament through the needle and past the insertion point to the injection site, wherein the needle insertion point is located at the needle tip and the needle injection site is substantially removed from the needle tip, and the needle tip is part of a retractable needle.