The present disclosure relates to a medical delivery device comprising a barrel having an inner surface, a stopper positioned within the barrel and a plunger rod or actuation mechanism to displace the stopper. The inner surface of the barrel has a water contact angle between 1° and 58°. The stopper contacts at least a portion of the inner surface of the barrel and has a compressibility of greater than 7.9% measured against the barrel. The stopper comprises two or more ribs, an elastomeric body and is at least partially covered with one or more non-fluoropolymer layers.
