A pharmaceutical syringe piston having a longitudinal axis and comprising: a body having: a central face portion oriented essentially perpendicularly with respect to the longitudinal axis of the piston and having a first outer circumference and a maximum first diameter (D F) measured perpendicularly to the longitudinal axis of the piston, a cylindrical sealing portion having a first axial end proximate the face portion, a second axial end, and a wall extending therebetween, and being oriented coaxially with respect to the longitudinal axis of the piston, the wall having an outer circumference and a diameter (D S) measured perpendicularly to the longitudinal axis of the piston and that is essentially constant along the longitudinal axis between the first and second axial ends of the cylindrical sealing portion, the diameter (D S) of the sealing portion being larger than the maximum first diameter (D F) of the central face portion, an annular curved portion connecting the first axial end of the cylindrical sealing portion to the first outer circumference of the central face portion, said annular curved portion having an outer diameter less than the first diameter (D S) of the cylindrical sealing portion; and an inert film enclosing the central face portion and at least a part of the annular curved portion, characterized in that: the shape of the annular curved portion exhibits an outwardly convex curve having a radius of curvature that extends into the body and the inert film has an outer boundary disposed between the first axial end of the cylindrical sealing portion and the first outer circumference of the central face portion. a body having: a central face portion oriented essentially perpendicularly with respect to the longitudinal axis of the piston and having a first outer circumference and a maximum first diameter (D F) measured perpendicularly to the longitudinal axis of the piston, a cylindrical sealing portion having a first axial end proximate the face portion, a second axial end, and a wall extending therebetween, and being oriented coaxially with respect to the longitudinal axis of the piston, the wall having an outer circumference and a diameter (D S) measured perpendicularly to the longitudinal axis of the piston and that is essentially constant along the longitudinal axis between the first and second axial ends of the cylindrical sealing portion, the diameter (D S) of the sealing portion being larger than the maximum first diameter (D F) of the central face portion, an annular curved portion connecting the first axial end of the cylindrical sealing portion to the first outer circumference of the central face portion, said annular curved portion having an outer diameter less than the first diameter (D S) of the cylindrical sealing portion; and a central face portion oriented essentially perpendicularly with respect to the longitudinal axis of the piston and having a first outer circumference and a maximum first diameter (D F) measured perpendicularly to the longitudinal axis of the piston, a cylindrical sealing portion having a first axial end proximate the face portion, a second axial end, and a wall extending therebetween, and being oriented coaxially with respect to the longitudinal axis of the piston, the wall having an outer circumference and a diameter (D S) measured perpendicularly to the longitudinal axis of the piston and that is essentially constant along the longitudinal axis between the first and second axial ends of the cylindrical sealing portion, the diameter (D S) of the sealing portion being larger than the maximum first diameter (D F) of the central face portion, an annular curved portion connecting the first axial end of the cylindrical sealing portion to the first outer circumference of the central face portion, said annular curved portion having an outer diameter less than the first diameter (D S) of the cylindrical sealing portion; and an inert film enclosing the central face portion and at least a part of the annular curved portion, characterized in that: the shape of the annular curved portion exhibits an outwardly convex curve having a radius of curvature that extends into the body and the inert film has an outer boundary disposed between the first axial end of the cylindrical sealing portion and the first outer circumference of the central face portion.