Metered dose spray device for use with macromolecular pharmaceutical agents such as insulin

A metered dose spray device for dispensing an effective amount of a macromolecular pharmaceutical agent against the oral mucosa of a user's mouth, comprising:

• a container for housing a solution comprising a macromolecular pharmaceutical agent and a propellant,
• a metering valve coupled to the container and having a metering chamber with a volume of from 100 μl to 600 μl;
• an actuator coupled to the metering valve and having an actuator sump with a volume of less than 45 mm3, the actuator sump defining at one end thereof a discharge orifice having a diameter of about 0.58 mm to 0.62 mm in communication with the atmosphere;
• wherein said metering valve is movable between a closed position in which the metering chamber is in fluid communication with the container but not the actuator sump such that a solution comprising a macromolecular pharmaceutical agent and a propellant housed in the container can flow into the metering chamber from the container, and an open position in which. the metering chamber is in fluid communication with the actuator sump but not the container such that a solution comprising a macromolecular pharmaceutical agent and a propellant contained in the metering chamber can flow into the actuator sump and be aerosolized by expansion of the propellant therein.