A containment assembly for enclosing a medication vial may comprise a first housing portion or interface portion having a proximal end and a distal end. The interface portion may include a housing wall which defines a channel spanning from the proximal end to the distal end. The channel may be open at the proximal and distal end. The containment assembly may further comprise at least one pierceable septum disposed at least at one of: on the proximal end of the channel and within the channel forming a barrier between the proximal end of the channel and distal end of the channel of the interface portion. The containment assembly may further comprise a variable-volume housing portion having a variable volume chamber. The variable-volume portion chamber of the variable-volume housing portion may be in fluid communication with the distal end of the channel.
