Abstract: A vacuum control system for a jet injector includes a power source and vacuum pump for creating suction at the injector tip. The injector includes a drive bar to expel medicament into the patient. Before injection the drive bar and an inner barrel are separated from each other, and at the end of the injection the drive bar contacts the inner barrel. A user operable switch that is moveable between an ON position and an OFF position is also provided. The power source, vacuum pump, drive bar, inner barrel and user operable switch are all electrically connected via an electrical circuit. The electrical circuit is configured to activate the vacuum pump when the user operable switch is in the ON position and the drive bar is separated from the inner barrel, and to deactivate the vacuum pump when the drive bar contacts the inner barrel.

Abstract: A device for providing medication for injection by a jet injector includes a cassette which connects an injector system to a reservoir. The cassette forms a fluid pathway at an interface of a cassette lower body and a cassette upper body. The cassette also forms an impulse chamber with a nozzle leading therefrom. The fluid pathway interconnects the reservoir with the impulse chamber. The medication flows from the reservoir along the fluid pathway and into the impulse chamber. Force from an impulse generator drives the fluid medicament from the impulse chamber through the nozzle, out an orifice in a tip of the nozzle, and into the skin of a patient. To prevent the pressure waves generated by the jet injector from breaking a glass cartridge in the reservoir, the fluid pathway is blocked, using a series of right angles or valves.

Abstract: A method for injecting a fluid medicament into a patient uses a syringe having a plunger that can be advanced into the syringe chamber. As the plunger is advanced, the medicament is expelled from the chamber through an injection tube that extends from the chamber. Preferably, the injection tube is formed as a cone-shaped funnel with a taper of generally decreasing radius in a distal direction. The steps for the method include creating a gas pocket in the distal portion of the injection tube. Then, as the plunger is advanced into the chamber to accelerate the fluid medicament through the injection tube, the gas pocket allows the accelerating fluid medicament to gain momentum. The change in this momentum as the fluid medicament collides with the skin will generate an impulse force that is manifested as an initial pressure spike. This pressure spike creates a hole in the skin of the patient as the fluid medicament exits the tube.

Abstract: An injector for the intra-muscular, subcutaneous, or intra-dermal delivery of a fluid medicament to a patient includes a cylindrical member which has a closed end and an open end, and which is formed with a compartment between these two ends. An injection tube extends from the closed end through the cylindrical member and into the compartment. A suction pump is connected in fluid communication with the compartment to create a partial vacuum in the compartment when the open end of the cylindrical member is held against the skin of the patient. Due to this vacuum, skin of the patient is drawn into the compartment to position the tip of the injection tube against the skin. Also, skin that is adjacent the tip is drawn by the vacuum into the compartment. This stabilizes the skin around the injection tube tip and thereby minimizes any movement of skin relative to the tip during an injection of fluid medicament into the patient.

Abstract: A jet injector, and a method, for injecting fluid medicament into a patient in a two-stage process. During the first stage fluid is expelled from the injector under relatively high pressure, to create a hole through the skin of the patient. During the second stage, fluid is infused through the hole into the patient at a much lower pressure, and for a much longer period of time. The jet injector includes a syringe unit, and a drive mechanism which is selectively connectable with the syringe unit. Specifically, the drive mechanism includes two springs which are positioned to urge against a push rod as they elongate. When the drive mechanism is engaged with the syringe unit, the push rod is positioned longitudinally co-linear with a plunger in the chamber. When the springs are released, they push the push rod which, in turn, pushes the plunger, causing the fluid to be expelled through an injection tube connected to the chamber.