A pre-filled syringe having containing therein at least one therapeutic is provided. The syringe contains a silicone free barrel and an elastomeric syringe stopper that is covered with an expanded polytetrafluoroethylene barrier layer. The presence of a barrier layer that is at least partially porous on the outside of the syringe stopper improves the seal between the stopper and syringe barrel and minimizes the sliding force. In some embodiments, the barrel is formed of a glass material such as a borosilicate glass, that is free of silicone or other lubricants.