Piston valving for serially connectable drug modules of a combinatorial drug delivery device

A combination comprising:

• a first module including:
• a first vial spike with a first free end, the first vial spike including a first inlet path open at the first free end and extending along the first vial spike to a first inlet opening, and a first outlet path open at the first free end and extending along the first vial spike to a first outlet chamber, the first outlet path being separate from the first inlet path;
• a first sealing port selectively sealing the first inlet opening;
• a first vent in communication with the first inlet path between the first inlet opening and the first free end;
• a slidable first piston valve located in the first outlet chamber, the first piston valve forming a seal in the first outlet chamber to define first and second primary chamber portions, the first outlet path being in communication with the first primary chamber portion;
• a first outlet fitting in communication with the second primary chamber portion;
• and,
• a first bypass passageway extending between the first outlet fitting and a first opening in the first outlet chamber,
• a second module including:
• a second vial spike with a second free end, the second vial spike including a second inlet path open at the second free end and extending along the second vial spike to a second inlet opening, and a second outlet path open at the second free end and extending along the second vial spike to a second outlet chamber, the second outlet path being separate from the second inlet path;
• a second sealing port selectively sealing the second inlet opening;
• a second vent in communication with the second inlet path between the second inlet opening and the second free end;
• a slidable second piston valve located in the second outlet chamber, the second piston valve forming a seal in the second outlet chamber to define first and second secondary chamber portions, the second outlet path being in communication with the first secondary chamber portion;
• a second outlet fitting in communication with the second secondary chamber portion;
• and,
• a second bypass passageway extending between the second outlet fitting and a second opening in the second outlet chamber,
• wherein, the second module is coupled to the first module with the second outlet fitting extending through the first seal port to be in communication with the first inlet opening,
• wherein, in an initial state, the first piston valve is located in a first position where the first primary chamber portion is sealed from the first bypass passageway,
• wherein, with negative pressure introduced through the first outlet fitting, the first piston valve is caused to move to a second position where the first primary chamber portion is in communication with the first bypass passageway, and,
• wherein, with the first piston valve in the second position, the negative pressure is introduced to the second outlet fitting via the first outlet path and the first inlet path.