Vortex feature for drug delivery system

An automatic injector comprising:

• a housing assembly having a central longitudinal axis;
• an interior chamber located within the housing assembly, the interior chamber having an inner side surface extending in the direction of the longitudinal axis;
• a needle assembly located within the housing assembly and in communication with the interior chamber to dispense a liquid solution from the interior chamber;
• and
• a seal structure positioned in the interior chamber to form a dry compartment and a wet compartment, the dry compartment suitable for containing a dry substance and the wet compartment suitable for containing a liquid, the seal structure positioned between the dry compartment and the wet compartment, the seal structure comprising:
• an outer seal that sealingly engages the inner side surface of the interior chamber to prevent liquid from passing between the outer seal and the inner surface of the chamber,
• a rigid member in communication with the outer seal,
• a flow path through the seal structure,
• a fluid-directing member in communication with the rigid member and the flow path and adjacent the dry compartment, the fluid-directing member comprising a helical channel;
• and
• an inner seal plug in communication with the rigid member having a first position with respect to the rigid member that closes the flow path to prevent passage of liquid through the flow path, the inner seal plug having a second position with respect to the rigid member that opens the flow path and allows a liquid in the wet compartment to flow through the flow path and the helical channel into the dry compartment.

An automatic injector comprising:

• a housing assembly having a central longitudinal axis;
• an interior chamber located within the housing assembly, the interior chamber having an inner side surface extending in the direction of the longitudinal axis;
• a needle assembly located within the housing assembly and in communication with the interior chamber to dispense a liquid solution from the interior chamber;
• and
• a seal structure positioned in the interior chamber to form a dry compartment and a wet compartment, the dry compartment suitable for containing a therapeutic agent and the wet compartment suitable for containing a liquid, the seal structure positioned between the dry compartment and the wet compartment and forming an annular seal between an outer surface of the seal structure and the inner side surface of the interior chamber, the annular seal preventing liquid from passing between the outer surface of the seal structure and the inner surface of the chamber, the seal structure having a sealed state and a flow-through state, the sealed state preventing liquid from passing through the seal structure and the flow-through state allowing liquid to pass through the seal structure, the seal structure comprising:
• at least one channel within the seal structure at an end of the seal structure adjacent the dry compartment, the at least one channel in fluid communication with a by-pass channel in the seal structure and having a plurality of exit ports that open into the dry compartment, each of the exit ports arranged circumferentially around the central longitudinal axis, each of the exit ports having an opening oriented at an angle of between about 80° to 90° with respect to the central longitudinal axis.

A method of assembling an automatic injector for administration of a liquid solution, the method comprising:

• providing a housing having a hollow interior;
• providing a chamber having first and second ends and a longitudinal axis;
• attaching a plunger to the first end of the chamber;
• loading a liquid in the chamber;
• inserting a seal structure in the chamber to create first and second compartments, the seal structure having a sealed state and a flow-through state, the liquid located in the first compartment, the seal structure having a helical channel adjacent the second compartment, the helical channel configured to allow a liquid to pass there through from the first compartment to the second compartment such that the liquid enters the second compartment circumferentially at an angle of about 80° to 90° with respect to the longitudinal axis of the chamber when the seal structure is in the flow-through state;
• loading a dry substance in the second compartment;
• attaching a needle assembly to the second end of the chamber;
• and
• placing the chamber, needle assembly, and plunger in the housing.

A method of preparing a liquid solution in an automatic injector, the liquid solution comprising a liquid and a dry substance, the method comprising:

• loading a liquid in a first compartment of a chamber, the chamber having a longitudinal axis;
• loading a dry substance in a second compartment of the chamber, the first and second compartments separated from each other by a seal structure having a sealed state and a flow-through state, the seal structure initially in the sealed state, the sealed state sealing the first compartment from the second compartment to prevent the liquid from flowing into the second compartment;
• converting the seal structure from the sealed state to the flow-through state to allow the liquid to flow from the first compartment into the second compartment;
• and
• forcing the liquid to flow into the second compartment in the form of a vortex to mix with the dry substance.