Described is a needle assembly reuse prevention mechanism (1) comprising a barrier (3) movable between a retracted position and an extended position, a spring coupled to the barrier (3), a pin (6) formed on the barrier (3), and a slot (9) receiving the pin (6). When in the extended position, the barrier (3) substantially covers an opening of a needle assembly storage compartment (2). The spring forces the barrier (3) in a first direction. The slot (9) has at least one abutment face for abutting the pin (6) and preventing movement of the barrier (3) in the first direction.
