Claims for Patent: 5,092,843

Summary for Patent: 5,092,843

Title:	Dispersion multichamber auto-injector
Abstract:	A medicament container assembly for an autoinjector having a power assembly actuatable to cause a power stroke in cooperating relation with said medicament container assembly. The medicament container assembly comprises a container having a forward end, a hypodermic needle having a sharpened end, and first and second liquid medicaments. A pair of pistons and a closure assembly are provided for (1) sealingly confining the first liquid medicament and the needle in mutually communicating relation in a forward storage position within the container, (2) sealingly confining the second liquid medicament within the container in a separate rearward storage position, and (3) enabling the power stroke to cause (1) an initial movement of the needle into the injection site during which the sharpened end of the needle moves from a position of entry into the skin to a full depth position, (2) a progressive movement of the first medicament outwardly of the sharpened end of the needle as the sharpened end of the needle moves from the position of entry into the skin into the full depth position so as to inject a predetermined dosage of the first liquid medicament within the injection site in a first pattern surrounding the path of movement of the sharpened end of the needle, and (3) a progressive movement of the second medicament outwardly of the sharpened end of the needle generally after the sharpened end of the needle has reached the full depth position thereof to inject a predetermined dosage of the second liquid medicament within the injection site in a second pattern extending from the sharpened end of the needle.
Inventor(s):	Monroe; O. Napoleon (Bethesda, MD), Dalling; N. Lawrence (Cross Junction, VA), Mesa; Clarence M. (Rockville, MD)
Assignee:	Survival Technology, Inc. (Bethesda, MD)
Application Number:	07/507,756
Patent Claims:	1. An auto-injector comprising a medicament cartridge assembly, a stressed spring assembly, and means mounting said assemblies together in cooperating relation so as to provide an exterior housing having a needle extending end, said medicament cartridge assembly including a container having one end disposed adjacent the needle extending end of said housing, first piston means mounted in a storage position within said container in spaced relation with the one end thereof for movement therein from the storage position thereof through an operative stroke in a direction toward the one end thereof, a hollow hypodermic needle having a sharpened end and an opposite inlet end portion disposed within said container in a storage position to be moved therefrom by and with said first piston means during the operative stroke thereof, closure means enclosing the sharpened end of said needle and the one end of said container disposed in a position to be penetrated by the sharpened end of said needle when said needle is moved with said first piston means, a first liquid medicament within said container in a storage position between said first piston means and said closure means, second piston means mounted in a storage position within said container in spaced relation with respect to the storage position of said first piston means for movement from the storage position thereof through an operative stroke in a direction toward said closure means, a second liquid medicament in said container disposed in a storage position in motion transmitting relation between said second piston means and said first piston means in sealed relation with respect to said first liquid medicament, the operative relation of said first liquid medicament and said needle between said first piston means and said closure means when in said storage positions within said container being such that when said first piston means is moved through the operative stroke thereof said needle is moved by said first piston means so that (1) during an initial portion of the movement of said needle with said first piston means the sharpened end of said needle penetrates through said closure means beyond the needle extending end of said housing and into the skin of a user without significant passage of said first liquid medicament from the sharpened end of the needle and (2) during the remaining portion of the movement of the needle with the first piston means, the first liquid medicament is moved into the inlet end of the needle and out of the sharpened end thereof and into the tissue of the user as the sharpened end moves inwardly of the skin into a full depth position, said stressed spring assembly including spring means, releasable means for retaining said spring means in a stressed storage position, and releasing means operable in response to a predetermined manual actuating procedure to release said releasable means so that said spring means moves said second piston means through the operative stroke thereof during an initial portion of which said first piston means is moved through the operative stroke thereof, said medicament cartridge assembly including bypass means operable in response to the movement of said first piston means through a final portion of the operative stroke thereof to allow a subsequent remaining portion of the operative stroke of said second piston means to move said second liquid medicament beyond said first piston means through said needle and out of the sharpened end thereof generally after the sharpened end has reached its full depth position. 2. An auto-injector as defined in claim 1 wherein said first piston means comprises a first piston having a resilient periphery, said container including a first interior generally cylindrical surface disposed in sealing engagement with the resilient periphery of said first piston and extending therefrom toward said closure means so as to be slidably sealingly engaged by the resilient periphery of said first piston during the operative stroke thereof. 3. An auto-injector as defined in claim 2 wherein said bypass means is located at an end portion of said first interior cylindrical surface adjacent the closure means and is operable to allow the second liquid medicament to move beyond said first piston exteriorly of the resilient periphery thereof. 4. An auto-injector as defined in claim 3 wherein said bypass means includes a cylindrical bypass surface extending from said one end of said container beyond said closure means a distance slightly greater than the longitudinal extent of the resilient periphery of said first piston and terminating at the forward end of said first interior cylindrical surface so as to provide an annular passageway around the resilient periphery of said first piston when said first piston moves in longitudinally coextensive relation thereto. 5. An auto-injector as defined in claim 4 wherein said inlet end portion of said needle includes a motion transmitting head fixed on the extremity of said needle and an inlet opening communicating transversely with the hollow interior of said needle adjacent said head. 6. An auto-injector as defined in claim 5 wherein said closure member includes an annular portion extending within the one end of said container and defining a recess within which the sharpened end of said needle is disposed in the storage position thereof and a needle guide fixed within said annular portion having an opening through which said needle extends, said needle guide being shaped to (1) engage said needle head when the sharpened end of said needle reaches its full depth position and (2) maintain a liquid flow path into the inlet opening of said needle adjacent to said head. 7. An auto-injector as defined in claim 6 wherein said second piston means comprises a second piston having a resilient periphery of a diameter size greater than the diameter size of the resilient periphery of said first piston, said container including a second interior generally cylindrical surface disposed in sealing engagement with the resilient periphery of said second piston and extending therefrom toward the first interior cylindrical surface so as to be slidably sealingly engaged by the resilient periphery of said second piston during the operative stroke thereof, said container providing a shoulder between said first and second interior cylindrical surfaces defining the end of the operative stroke of said second piston. 8. An auto-injector as defined in claim 7 wherein said releasing means includes an outer tubular releasing member, said assembly mounting means including a tubular member providing a substantial part of said housing, said housing providing tubular member being fixedly connected with said tubular releasing member and mounted for movement therewith in surrounding telescopic relation with respect to a substantial portion of said container, said releasing means further including a safety cap structure having a skirt portion normally positioned over said tubular releasing member, said predetermined actuating procedure including removing said safety cap structure manually from its normal position and moving the needle extending end of said housing toward the injection site by manually gripping said housing providing tubular member until a relative longitudinal movement of said tubular members with respect to said container in a direction toward the injection site takes place as a result of the injection site stopping the movement of the container, said releasable means being released in response to said relative longitudinal movement. 9. An auto-injector as defined in claim 8 wherein said releasable means comprises an inner tubular member disposed within said outer tubular releasing member and an elongated member having spaced fingers on one end thereof movable laterally from a locking position inwardly into a releasing position, said inner tubular member including an end wall having a central aperture therein, said fingers having locking surfaces spaced from free ends thereof for engaging locking surfaces on the end wall of said inner tubular member and releasing surfaces between said locking surfaces and the free ends thereof, said spring means comprising a helical coil spring surrounding said elongated member, said elongated member having means on the end thereof opposite from said fingers for engaging one end of said coil spring, said elongated member in a storage position releasably retaining said coil spring in a compressively stressed condition with, free end portions of said fingers extending through the central aperture of the end wall of said inner tubular member and with the locking surfaces thereof engaging the locking surfaces on the end wall of said inner tubular member, said safety cap structure including a central safety rod disposed between said fingers when said safety cap structure is in its normal position so as to prevent lateral movement of said fingers and hence disengagement of said locking surfaces, said outer tubular releasing member including an end wall having releasing surfaces positioned to engage the releasing surfaces of said fingers during the relative longitudinal movement of said tubular members with respect to said container to cause said fingers to move laterally inwardly when said safety rod is removed and disengage said locking surfaces to release said spring means to thereby move said elongated member through an operative stroke during which said second piston is moved through the operative stroke thereof. 10. An auto-injector as defined in claim 9 wherein the operative relation of said first liquid medicament and said needle between said first piston means and said closure means in the storage positions thereof within said container is one in which the volume of first liquid medicament and needle is less than the volume within said container between said first piston means and said closure means so as to leave a volume of gas therein which is compressed during the initial portion of the movement of the needle as aforesaid. 11. An auto-injector as defined in claim 10 wherein said first liquid medicament is atropine. 12. An auto-injector as defined in claim 11 wherein said second liquid medicament is 2-pralidoxime chloride. 13. An auto-injector as defined in claim 2 wherein said second piston means comprises a second piston having a resilient periphery of a diameter size greater than the diameter size of the resilient periphery of said first piston, said container including a second interior generally cylindrical surface disposed in sealing engagement with the resilient periphery of said second piston and extending therefrom toward the first interior cylindrical surface so as to be slidably sealingly engaged by the resilient periphery of said second piston during the operative stroke thereof, said container providing a shoulder between said first and second interior cylindrical surfaces defining the end of the operative stroke of said second piston. 14. An auto-injector as defined in claim 1 wherein said inlet end portion of said needle includes a motion transmitting head fixed on the extremity of said needle and an inlet opening communicating transversely with the hollow interior of said needle adjacent said head. 15. An auto-injector as defined in claim 14 wherein said closure member includes an annular portion extending within the one end of said container and defining a recess within which the sharpened end of said needle is disposed in the storage position thereof and a needle guide fixed within said annular portion having an opening through which said needle extends, said needle guide being shaped to (1) engage said needle head when the sharpened end of said needle reaches its full depth position and (2) maintain a liquid flow path into the inlet opening of said needle adjacent to said head. 16. An auto-injector as defined in claim 1 wherein said releasing means includes an outer tubular releasing member, said assembly mounting means including a tubular member providing a substantial part of said housing, said housing providing tubular member being fixedly connected with said tubular releasing member and mounted for movement therewith in surrounding telescopic relation with respect to a substantial portion of said container, said releasing means further including a safety cap structure having a skirt portion normally positioned over said tubular releasing member, said predetermined actuating procedure including removing said safety cap structure manually from its normal position and moving the needle extending end of said housing toward the injection site by manually gripping said housing providing tubular member until a relative longitudinal movement of said tubular members with respect to said container in a direction toward the injection site takes place as a result of the injection site stopping the movement of the container, said releasable means being released in response to said relative longitudinal movement. 17. An auto-injector as defined in claim 16 wherein said releasable means comprises an inner tubular member disposed within said outer tubular releasing member and an elongated member having spaced fingers on one end thereof movable laterally from a locking position inwardly into a releasing position, said inner tubular member including an end wall having a central aperture therein, said fingers having locking surfaces spaced from free ends thereof for engaging locking surfaces on the end wall of said inner tubular member and releasing surfaces between said locking surfaces and the free ends thereof, said spring means comprising a helical coil spring surrounding said elongated member, said elongated member having means on the end thereof opposite from said fingers for engaging one end of said coil spring, said elongated member in a storage position releasably retaining said coil spring in a compressively stressed condition with free end portions of said fingers extending through the central aperture of the end wall of said inner tubular member and with the locking surfaces thereof engaging the locking surfaces on the end wall of said inner tubular member, said safety cap structure including a central safety rod disposed between said fingers when said safety cap structure is in its normal position so as to prevent lateral movement of said fingers and hence disengagement of said locking surfaces, said outer tubular releasing member including an end wall having releasing surfaces positioned to engage the releasing surfaces of said fingers during the relative longitudinal movement of said tubular members with respect to said container to cause said fingers to move laterally inwardly when said safety rod is removed and disengage said locking surfaces to release said spring means to thereby move said elongated member through an operative stroke during which said second piston means is moved through the operative stroke thereof. 18. An auto-injector as defined in claim 1 wherein the operative relation of said first liquid medicament and said needle between said first piston means and said closure means in the storage positions thereof within said container is one in which the volume of first liquid medicament and needle is less than the volume within said container between said first piston means and said closure means so as to leave a volume of gas therein which is compressed during the initial portion of the movement of the needle as aforesaid. 19. An auto-injector as defined in claim 1 wherein said first liquid medicament is atropine. 20. An auto-injector as defined in claim 19 wherein said second liquid medicament is 2-pralidoxime chloride. 21. A medicament container assembly for an auto-injector having a power assembly actuatable to cause an elongated element thereof to move through a power stroke in cooperating relation with said medicament container assembly, said medicament container assembly comprising a container having a forward end, a hypodermic needle having a sharpened end, first and second liquid medicaments, means for (1) sealingly confining said first liquid medicament and said needle in mutually communicating relation in a forward storage position within said container, (2) sealingly confining said second liquid medicament within said container in a rearward storage position separate from said first liquid medicament and said needle and (3) enabling a movement of the elongated element of the power assembly through a power stroke in cooperating relation with said medicament container assembly while the forward end of said container is held in cooperating relation with an injection site of a user to cause (1) an initial movement of said needle into the injection site during which the sharpened end of the needle moves from a position of entry into the skin to a full depth position, (2) a progressive movement of said first medicament outwardly of the sharpened end of said needle as the sharpened end of the needle moves from the position of entry into the skin into said full depth position so as to inject a predetermined dosage of said first liquid medicament within the injection site in a first pattern generally surrounding the path of movement of the sharpened end of said needle from the position of entry to the full depth position and (3) a progressive movement of said second medicament outwardly of the sharpened end of said needle generally after the sharpened end of the needle has reached the full depth position thereof to inject a predetermined dosage of said second liquid medicament within the injection site in a second pattern generally extending from the sharpened end of the needle in surrounding relation to the full depth position of the sharpened end of the needle. 22. A medicament container assembly as defined in claim 21 wherein the first medicament is atropine and the second medicament is 2-pralidoxime chloride, the volume of the predetermined dosage of said 2-pralidoxime chloride being greater than the volume of the predetermined dosage of said atropine.