Drug delivery device cassette

A drug delivery device comprising a cassette to couple to a reusable module, wherein the cassette comprises:

• a cartridge configured to retain a volume of a medication, the cartridge extending between a proximal end and a distal end along an axis that is centrally located;
• a stopper driving system configured to drive the medication from the cartridge, the stopper driving system comprising a stopper and an interfacing end coupled to the stopper and configured to be driven by a first motor or a first actuating device of the reusable module to move the stopper;
• and
• a needle assembly directly coupled to the cartridge and movable between an extended configuration and a retracted configuration, the needle assembly having an actuating gear rotatable in a first direction and a second direction opposite the first direction, the actuating gear configured to be directly or indirectly driven by a second motor of the reusable module, wherein in the extended configuration after rotation of the actuating gear in the first direction the needle assembly is configured to provide fluid communication between the cartridge and the needle assembly, wherein in the retracted configuration after rotation of the actuating gear in the second direction no fluid communication is provided between the cartridge and the needle assembly, wherein the needle assembly is moved to the retracted configuration after being in the extended configuration,
• wherein the interfacing end extends from an upper end of the cartridge and coaxial with the axis, and the actuating gear is disposed at a location offset from the axis, and
• wherein the drug delivery device further comprises the reusable module, the reusable module comprising the first motor configured to actuate the stopper driving system to deliver the medication from the cartridge, and the second motor configured to actuate the actuating gear of the needle assembly.