Cap systems with piercing member for pharmaceutical vials

A cap system for a pharmaceutical vial having an interior in which a flowable material is disposed, an opening to the interior of the vial and a flanged neck surrounding the opening, the flanged neck having an undersurface, said cap system comprising:

• an elastomeric stopper configured to be secured to the vial;
• a retainer member including first portions configured to be secured to the vial with said first portions flexing over the flanged neck of the vial and then snapping into engagement with the undersurface of the flanged neck of the vial;
• a locking member comprising a peripheral sidewall including inwardly projecting members, said locking member being slidable to a position with respect to said retainer member whereupon said inwardly projecting members apply an inward force on said first portions of said retainer member to permanently seal said vial;
• a cap member movable with respect to said locking member from a retracted position to an extended position;
• and
• a piercing member coupled to said cap member and having a piercing tip configured to pierce through said elastomeric stopper into the interior of the vial when said cap member is moved to said extended position.