Disposable needle-free injection apparatus and method

A needle-free injection system comprising:

• a nozzle portion having a glass wall defining a drug storage space, and an injection wall defining a drug injection space, the injection wall being coaxial with the glass wall and defining a plurality of axially-extending drug bypass conduits that interconnect with a plurality of radially-extending drug bypass conduits;
• an injection orifice defined at a forward end of the injection space;
• a drug plunger defining a rearward end of the storage space;
• a drug plug initially disposed between the storage space and the injection space, and being displaceable into a forward-most position adjacent the bypass conduits;
• and
• a pierceable gas cartridge for providing injection power to the system.

A needle-free injection system comprising:

• a nozzle portion having a glass wall defining a drug storage space, and an injection wall defining a drug injection space, the injection wall being coaxial with the glass wall and defining a plurality of axially-extending drug bypass conduits disposed adjacent a forward end of the injection space;
• an injection orifice defined at the forward end of the injection space;
• a drug plunger defining a rearward end of the storage space;
• a drug plug initially disposed between the storage space and the injection space, and being displaceable into the injection space adjacent the bypass conduits;
• a pierceable gas cartridge for providing injection power to the system;
• a gas piston extending toward the drug plunger to convey injection power between the gas cartridge and the drug plunger;
• wherein the drug plunger and drug plug are initially spaced with respect to each other, disposed within the glass cartridge, and exertion of force on the drug plunger pushes the drug plunger and drug plug in a forward direction along with any drug disposed therebetween, until the drug plug is in a forward-most position, at which time drug flows through the bypass conduits and around the drug plug, thereby displacing any air in the injection space and priming the system.

A needle-free injection system comprising:

• a nozzle portion having a glass wall defining a drug storage space, and an injection wall defining a drug injection space, the injection wall being coaxial with the glass wall;
• an injection orifice defined at a forward end of the injection space;
• a drug plunger defining a rearward end of the storage space;
• a pierceable gas cartridge for providing injection power to the system;
• a gas pressure rod positioned rearwardly of and coaxial with the drug plunger, the gas pressure rod defining an axially extending gas channel and at least one radially extending gas channel;
• a seal ring disposed around the gas pressure rod positioned to receive gas pressure when the gas cartridge has been pierced, the gas pressure exerting a forward force on the seal ring, the seal ring being slidable between positions rearward and forward of the radial gas channel, the seal ring sealing gas pressure from passing forwardly of the seal ring, such that when the seal ring is disposed forwardly of the radial gas channel, gas pressure can pass through the radial channel and into the axial channel and be directed forwardly to drive the drug plunger forwardly;
• a trigger member disposed forwardly of the seal ring and being positioned and configured such that when forward force is exerted on the angled face, the trigger member is biased radially outwardly;
• a trigger actuator disposed radially outwardly of the trigger member to hold the trigger member in place against the outward bias exerted when the gas cartridge is pierced, so that when the system is actuated and the trigger actuator is moved away from the trigger member, a path is cleared for the trigger member to move radially outwardly;
• and
• a sliding member disposed between the seal member and the trigger member and having a forward face in contact with the trigger member, the forward face of the sliding member being angled to complement the trigger member face so that when the gas cartridge is pierced and forward force is exerted on the seal ring, forward force is conveyed to the sliding member, and the angled face of the sliding member and the trigger member cooperate to exert a radially outward force on the trigger member.

A needle-free injection system comprising:

• a nozzle portion defining a forwardly-facing injection orifice;
• a body portion mounted to the nozzle portion, the portions being displaceable toward each other to prepare the system for actuation;
• and
• a safety tab for preventing actuation prior to the time that relative displacement is effected between the nozzle portion and the body portion, the safety tab being fragibly mounted to one of the body portion or the nozzle portion and including a contact part, the safety tab to be contacted and broken when the portions are displaced toward each other.

A method of preparing a needle-free injection unit for injection, the method comprising:

• providing a storage compartment for liquid drug;
• defining an injection orifice forwardly of the storage compartment, through which the liquid drug is selectively injected into the patient;
• providing a pressurized, pierceable gas storage cartridge with a system for conveying pressure to the storage compartment when the cartridge is pierced;
• positioning a seal between the cartridge and the storage compartment to prevent gas pressure from reaching the storage compartment after the cartridge is pierced, but prior to actuation of the unit, the seal being positioned such that the piercing of the cartridge provides axial pressure on the seal;
• providing a trigger having an angled face positioned such that when axial pressure is provided on the trigger, an outward force is exerted on the trigger;
• and
• positioning a trigger actuator outwardly of the trigger to prevent the trigger from moving outwardly until the unit is actuated.

A method of performing a needle-free injection using a needle-free injection unit, the method comprising:

• providing a storage compartment for liquid drug;
• positioning an injection orifice forwardly of the storage compartment, through which the liquid drug is selectively injected into the patient;
• providing a pressurized, pierceable gas storage cartridge with a system for conveying pressure to the storage compartment when the cartridge is pierced;
• positioning a seal between the cartridge and the storage compartment to prevent gas pressure from reaching the storage compartment prior to actuation of the unit, the seal being positioned such that the piercing of the cartridge provides axial pressure on the seal;
• providing a trigger having a roller positioned such that when axial pressure is provided on the trigger, an outward force is exerted on the trigger;
• positioning a trigger actuator outwardly of the trigger to prevent the trigger from moving outwardly until the unit is actuated, wherein actuation of the unit causes displacement of the trigger actuator, clearing the way for the trigger to move outwardly;
• providing a path of movement for the seal such that when the trigger moves radially outwardly, the seal is free to move in the path of movement;
• providing a pressure path that is clear to provide pressure to the storage compartment once the seal moves in its path of movement, such that providing pressure to the storage compartment forces liquid drug from the storage compartment, through the injection orifice and into the patient;
• piercing the cartridge to prepare the unit for injection;
• and
• after the cartridge is pierced, positioning the unit against the skin of the patient, and actuating the unit to effect injection.