Abstract: A syringe assembly (10) has a syringe barrel (12), a plunger rod (14) and stopper (16) where the syringe barrel has an open end receiving the plunger rod and stopper in a sliding direction. The plunger rod includes a shaft (52) having a longitudinal axis with a first end having a coupling member (62) for coupling with the stopper. The shaft has a least one plunger rod support (82) extending radially outer from the shaft and spaced from the first end for cooperating with an inner surface of the syringe barrel (12) to resist lateral movement and tilting of the plunger rod relative to the longitudinal axis of the axial passage of the syringe barrel. The shaft in one embodiment has at least two spaced apart points of support (41) and (82) for maintaining the axis of the plunger rod on axis with the syringe barrel to limit twisting and tilting of the stopper thereby resisting distortion of the stopper that can cause leakage.

Abstract: A syringe assembly (10) has a syringe barrel (12), a plunger rod (14) and stopper (16) where the syringe barrel has an open end receiving the plunger rod and stopper in a sliding direction. The plunger rod includes a shaft (52) having a longitudinal axis with a first end having a coupling member (62) for coupling with the stopper. The shaft has a least one plunger rod support (82) extending radially outer from the shaft and spaced from the first end for cooperating with an inner surface of the syringe barrel (12) to resist lateral movement and tilting of the plunger rod relative to the longitudinal axis of the axial passage of the syringe barrel. The shaft in one embodiment has at least two spaced apart points of support (41) and (82) for maintaining the axis of the plunger rod on axis with the syringe barrel to limit twisting and tilting of the stopper thereby resisting distortion of the stopper that can cause leakage.