Patent ID: 7727202
Filing Date: 2010-06-01
Classification: A61M

Abstract:
1. A piston stopper for an injection device for administering a medicinal substance, comprising: a cylindrical stopper body having a first side and a second side, the first and second sides being separated by a cylindrical wall, said first side being distal and facing the medicinal substance in the injection device, said second side being proximal and comprising a threaded section for coupling to a piston rod, and said cylindrical wall comprising one or more annular grooves; and at least one sealing ring arranged substantially within the one or more annular grooves, each sealing ring comprising a first contact area and a second contact area, the first contact area coupled by a material bond to one of the one or more annular grooves such that the at least one sealing ring is adhered to or integrally formed at a respective contact area in the one or more annular grooves of said stopper body, and wherein the second contact area projects substantially radially from the first contact area beyond the cylindrical body and contacts an inner wall of a cylinder of the injection device and has a substantially unvarying area, the second contact area comprising a proximal end and a distal end and a sealing tongue at the distal end, the sealing tongue contacting the inner wall of the cylinder of the injection device and being formed by a concave recess in said sealing ring, the concave recess being distally oriented, wherein, upon contact by liquid at the distal end of the sealing ring, the sealing tongue diverts liquid through the concave recess and away from the inner wall of the cylinder of the injection device.