METHODS AND APPARATUS FOR DELIVERING AEROSOLIZED MEDICATION

摘要

A metered dose inhaler for use with a pressurized aerosol canister includes a housing defining a conduit with a mouthpiece, and an actuator wit h a nozzle discharge orifice arranged to discharge aerosol into the conduit. An air tub e is arranged within the conduit with an inlet of the air tube formed in the conduit wall and an outlet of the air tube in opposing relationship with the nozzle orifice. Inhalation through the mouthpiece causes air to be drawn into the inlet and flow out of the outlet of the air tube to form an air jet which impinges on an oppositely moving aerosol plume from the orifice. Auxiliary air inlets in the closed end of the conduit provide a boundary layer flow along the inner wall of the conduit. Vortex generators on the inner wal l of the conduit add vorticity and turbulence to the boundary layer flow. Automatic actuation of the canister responsive to the patient's inhalation is achieved by a caniste r trigger connected to a movable piston assembly forming a wall of a variable-volume chamber in fluid communication with a venturi in the air tube. Air drawn through the venturi by the user's breath causes evacuation of air from the chamber, thereby moving the piston assembly and trigger to cause actuation of the canister.