Abstract: An aerosol introducer is provided for introducing an aerosolized pharmaceutical formulation into a ventilator circuit. The ventilator circuit comprises an endotracheal tube, an inhalation line extending from a ventilator, and an exhalation line extending from the ventilator. The aerosol introducer comprises a first end connectable to the inhalation line and the exhalation line; a second end connectable to the endotracheal tube; a first channel extending from the first end to the second end; a second channel extending from the first end to the second end; an inlet in the first channel, the inlet being adapted to receive an aerosolized pharmaceutical formulation; and a valving mechanism comprising one or more valves that reduce the loss of aerosolized pharmaceutical formulation to the exhalation line.