| abstract |
The invention provides an aerosol medication delivery apparatus for use with a pMDI canister having medication and a propellant contained therein under pressure, wherein the pMDI canister has a discharge orifice from which the medication and propellant can be discharged forming an aerosol. The apparatus has a chamber housing having an input end and an output end and defining an interior space, wherein the input end receives the medication discharged from the discharge orifice of the pMDI canister into the interior space and wherein the medication can be withdrawn from the interior space by inhalation by a patient from the output end. The aerosol medication delivery apparatus also includes a valve at the output end. The valve has a valve seat and a valve member. The valve seat has a sealing surface and the valve member has a central open area and a sealing portion at the perimeter of the open area that mates with the sealing surface when the valve is closed. The valve allows medication to be withdrawn through the central open area but prevents backflow into the chamber housing. |