Device and method of creating aerosolized mist of respiratory drug

Abstract

Devices, packaging and methodology for efficiently and repeatably creating aerosolized bursts of a formulation of respiratory drug are disclosed. Devices are hand-held, self-contained units which are automatically actuated at the same release point in a patient's inspiratory flow cycle. The release point is automatically determined either mechanically or, more preferably calculated by a microprocessor which receives data from a sensor making it possible to determine inspiratory flow rate and inspiratory volume. The device is loaded with a cassette comprised of an outer housing which holds a package of individual collapsible containers of formulation which comprises a respiratory drug useful in topically treating lung tissue. Actuation of the device forces respiratory drug through a porous membrane of the container which membrane has pores having a diameter in the range of about 0.25 to 6.0 microns. The porous membrane is positioned in alignment with a surface of a channel through which a patient inhales air. The flow profile of air moving through the channel is such that the flow at the surface of the channel is less than the flow rate at the center of the channel. The membrane is designed so that it protrudes outward at all times or is made flexible so that when respiratory drug formulation is forced against and through the membrane the flexible membrane protrudes outward beyond the flow boundary layer of the channel into faster moving air. Because the membrane protrudes into the faster moving air of the channel the particles of aerosol formed are less likely to collide allowing for the formation of a burst of fine aerosol mist with uniform particle size.