Apparatus for delivery of a medicament to a breathing system, the apparatus comprising: a nebulizer that is adapted to aerosolize a liquid medicament to be delivered to a patient's respiratory system; and a connector that operably connects the nebulizer to a circuit of a pressure-assisted breathing system; wherein the connector comprises: a gas conduit having an inlet opening and an outlet opening adapted to be attached to the circuit so that the flow of gas in the circuit is conducted therethrough; an aerosol supply conduit having an inlet opening adapted to receive the nebulizer and an outlet opening that communicates with the gas conduit so that aerosolized medicament is conducted from the nebulizer to the gas flow in the gas conduit; and a sealing device comprising a spring-loaded hinged door positioned within the gas conduit adjacent to the aerosol supply conduit outlet opening, wherein the nebulizer forces the hinged door into an open position when the nebulizer is received in the aerosol supply conduit, and wherein the spring on the hinged door forces the door over the aerosol supply conduit outlet opening when the nebulizer is removed from the aerosol supply conduit, the apparatus characterized in that; said gas conduit comprises a notch or recess in an internal wall; and that when the hinged door is in the open position it is in cooperation with the notch or recess in the internal wall of the gas conduit thereby allowing unimpeded flow of aerosol from the nebulizer into the gas conduit. a nebulizer that is adapted to aerosolize a liquid medicament to be delivered to a patient's respiratory system; and a connector that operably connects the nebulizer to a circuit of a pressure-assisted breathing system; wherein the connector comprises: a gas conduit having an inlet opening and an outlet opening adapted to be attached to the circuit so that the flow of gas in the circuit is conducted therethrough; an aerosol supply conduit having an inlet opening adapted to receive the nebulizer and an outlet opening that communicates with the gas conduit so that aerosolized medicament is conducted from the nebulizer to the gas flow in the gas conduit; and a sealing device comprising a spring-loaded hinged door positioned within the gas conduit adjacent to the aerosol supply conduit outlet opening, wherein the nebulizer forces the hinged door into an open position when the nebulizer is received in the aerosol supply conduit, and wherein the spring on the hinged door forces the door over the aerosol supply conduit outlet opening when the nebulizer is removed from the aerosol supply conduit, the apparatus characterized in that; said gas conduit comprises a notch or recess in an internal wall; and that a gas conduit having an inlet opening and an outlet opening adapted to be attached to the circuit so that the flow of gas in the circuit is conducted therethrough; an aerosol supply conduit having an inlet opening adapted to receive the nebulizer and an outlet opening that communicates with the gas conduit so that aerosolized medicament is conducted from the nebulizer to the gas flow in the gas conduit; and a sealing device comprising a spring-loaded hinged door positioned within the gas conduit adjacent to the aerosol supply conduit outlet opening, wherein the nebulizer forces the hinged door into an open position when the nebulizer is received in the aerosol supply conduit, and wherein the spring on the hinged door forces the door over the aerosol supply conduit outlet opening when the nebulizer is removed from the aerosol supply conduit, the apparatus characterized in that; said gas conduit comprises a notch or recess in an internal wall; and that