Medication delivery device including disposable and reusable portions

A medication delivery device, comprising:

• a disposable portion comprising a housing having a distal end, a therapeutic agent delivery assembly translatably carried in the housing, the therapeutic agent delivery assembly having a chamber comprising a passageway configured to carry a therapeutic agent, and a needle in communication with the passageway, a biasing element carried in the housing, the biasing element biasing the therapeutic agent delivery assembly toward a stowed configuration, in the stowed configuration the needle being disposed proximally relative to the distal end of the housing;
• and a proximal cover carried by the housing, the proximal cover retaining the therapeutic agent delivery assembly in the housing, and the proximal cover comprising a mechanical or magnetic configured to detachably secure the disposable portion to the reusable portion;
• the therapeutic agent delivery assembly being translatable by the reusable portion relative to the housing from the stowed configuration to a deployed configuration, in the deployed configuration the needle at least partially extending distally from the distal end of the housing;
• and
• a reusable portion comprising a reusable portion housing, a drive mechanism carried by the reusable portion housing, the drive mechanism comprising:
• a first rack and pinion mechanism;
• a frame translatably carried by the reusable portion housing via the first rack and pinion mechanism;
• a second rack and pinion mechanism coupled to the frame;
• a plunger translatably carried by the frame via the second rack and pinion mechanism;
• the first rack and pinion mechanism being actuatable to translate the frame relative to the reusable portion housing to translate the therapeutic agent delivery assembly from the stowed configuration to the deployed configuration, and the second rack and pinion mechanism being actuatable to translate the plunger relative to the housing of the disposable portion to a position closer to the needle of the therapeutic agent delivery assembly.

A disposable portion for a medication delivery device, the medication delivery device comprising a reusable portion configured to detachably carry the disposable portion, the disposable portion comprising:

• a disposable portion housing having a proximal end and a distal end;
• a syringe translatably carried in the housing, the syringe having a chamber comprising a passageway configured to carry a therapeutic agent, and a needle in communication with the passageway;
• a proximal stop element surrounding the chamber of the syringe;
• a compression spring carried in the disposable portion housing, the compression spring biasing the syringe toward a stowed configuration, in which the needle of the syringe is disposed proximally relative to the distal end of the housing;
• and
• a proximal cover coupled to the proximal end of the disposable portion housing, the proximal cover retaining the syringe and the compression spring in the disposable portion housing, the proximal cover including a main body and an inner passageway sized to inhibit proximal movement of the therapeutic agent delivery assembly through the inner passageway, the proximal cover comprising a connector to detachably secure the disposable portion to the reusable portion, wherein the syringe is translatable by the reusable portion relative to the disposable portion housing from the stowed configuration to a deployed configuration, in the deployed configuration the needle of the syringe is at least partially extended distally from the distal end of the disposable portion housing,
• wherein the compression spring is disposed between the proximal stop element and a position along the syringe, and the compression spring is configured to bias the proximal stop element against an inside of the proximal cover.