Vial adapter and system

A vial adapter for use with a vial having a neck with a passage in the neck and a rim disposed adjacent the neck, a stopper disposed over the passage in the neck of the vial to control access through the passage into the vial, and a crimp ring disposed about the stopper and the rim to maintain the stopper fixed relative to the vial, the vial adapter comprising:

• first and second sections each having first and second ends that are joined with the opposing first and second ends of the other collar section to form a collar having an inner surface defining a central passage in which the neck of the vial is disposed,
• each of the collar sections having a hook formed at each end of the collar section, the hooks of opposing ends of the collar sections joined to each other to join the collar sections together,
• the first ends of each of the collar sections having at least one tab depending therefrom and the second ends of each of the collar sections having at least one indent formed therein, the at least one tab disposed within the at least one indent with the hooks of opposing ends of the collar sections joined to each other, and
• the inner surface having a groove formed therein, the groove separating the collar into first and second regions,
• the first and second regions being deformable axially into the groove when the collar is acted upon by the vial with the neck of the vial disposed in the central passage.