616293 A plunger assembly (30) for a syringe, particularly a passive reuse prevention syringe assembly (10). The plunger assembly (30) comprising: an elongate plunger rod (31) a plunger head (32) having a distal sealing surface (33) and a proximal end surface (36), the proximal end surface (36) of the plunger head (32) having a continuous perimeter adapted to provide a parimetrical engagement with a chamber of a syringe barrel (20) and a breakable neck portion (37) extending between the plunger rod (31) and the proximal end surface of the plunger head (32). The plunger rod (31) and the plunger head (32) are integrally connected by the breakable neck portion (37), and the plunger assembly (30) is formed as a single, monolithic piece.
