Container closure system and sealing assemblies for maintaining seal integrity at low storage temperatures

A sealed pharmaceutical container comprising:

• a central axis;
• an opening;
• a shoulder;
• a neck extending from the shoulder;
• a flange circumferentially surrounding the opening, the flange comprising:
• an underside surface extending from the neck;
• an outer surface extending from the underside surface, the outer surface defining an outer radius ro of the flange;
• an upper surface, wherein, in a cross-section of the sealed pharmaceutical container taken through a plane extending parallel to and through the central axis, the upper surface comprises a first linear section disposed on a first side of the opening and a second linear section disposed on the second side of the opening, wherein outer ends of the first and second linear sections are disposed a distance 2*rsr apart from one another in a direction perpendicular to the central axis;
• and
• a transition region extending between the upper surface and the outer surface;
• and
• a sealing assembly comprising:
• a stopper comprising an insertion portion inserted into the opening and a sealing portion in contact with the upper surface, wherein the sealing portion comprises a stepwise transition in a radial dimension at a location that is axially offset from the upper surface;
• and
• a cap compressing the stopper against the upper surface, wherein the sealing portion comprises a compressed radius rsc that is less than rsr adjacent the upper surface.