Abstract: An IN delivery gas-phase impermeable device for delivery between 0.2 mL and 1.0 mL of a medication solution is disclosed. The device includes an injector barrel including a plurality of slit openings disposed circumferentially along the injector barrel, a center guide positioned lengthwise within the injector barrel, a cannula in fluid communication with the medication solution fixed in position by the center guide, and a vial configured to couple with the injector barrel. The vial includes a pliable rubber stopper with multiple seal rings, each seal ring having a geometry configured to form a gas-phase impermeable seal with an internal surface of the vial. The cannula bisects the pliable rubber stopper. The device includes a base configured to reversibly engage with one or more of the slit openings of the injector barrel during actuation of the device, which may involve compression of the base toward the injector barrel.