Abstract: A spacer for delivering a medicinal substance is provided having a chamber having a tubular body defining a first reservoir, the top end of the body narrowing to define a single unobstructed central chamber aperture, a base for the body having an inlet for admission of the substance into the first reservoir, a vented member connected atop the body, a mouthpiece connected atop the vented member and partly defining a second reservoir, the mouthpiece having an outlet for withdrawal of the substance from the second reservoir The spacer also has a valve within the chamber having a self-supporting central domed portion and defining a central cross slit at its peak, the domed portion opening during inspiration and closing during expiration, and a flat ringed portion surrounding the domed portion with a circumferential free edge, the diameter of the ringed portion being approximately twice the diameter of the domed portion.

Abstract: A spacer comprising a polycarbonate chamber and a flow valve located within the chamber. The chamber comprises: a first reservoir and a second reservoir; an inlet for admission of aerosolized medication into the first reservoir; an outlet for withdrawal of medication from the second reservoir; and a vent for expulsion of air from the second reservoir. The flow valve is adapted to: allow forward-flow of medication from the first reservoir to the second reservoir during user inspiration; substantially limit inflow of air through the vent into the second reservoir during user inspiration, substantially limit backflow of air or medication from the second reservoir to the first reservoir during user expiration; and allow expulsion of air from the second reservoir through the vent during user expiration.