A pharmaceutical drug delivery device and method of preventing drying out and drooling of an ejection head for the drug delivery device. The device includes a device body; a fluid outlet nozzle attached to the device body; and a fluid jet ejection cartridge containing a liquid pharmaceutical drug disposed in the body. A fluid ejection head is attached to the fluid jet ejection cartridge and is in fluid flow communication with the fluid outlet nozzle. An elongate, serpentine air flow path disposed between an inner surface of the fluid outlet nozzle and a sealing material that is disposed between an outer surface of the fluid jet ejection cartridge and the inner surface of the fluid outlet nozzle, wherein the elongate, serpentine air flow path provides a reduced pressure differential adjacent to a surface of the ejection head upon use of the drug delivery device and provides a humidification zone.