The AER^sub x^ (TM) Aerosol Delivery System

We describe the AERX aerosol delivery system, a new, bolus inhalation device that is actuated at preprogrammed values of inspiratory flow rate and inhaled volume. We report on its in vitro characterization using a particular set of conditions used in pharmacokinetic and scintigraphic studies. Multiple doses of aerosol were delivered from single use collapsible plastic containers containing liquid formulation. The aerosol was generated by forcing the formulation under pressure through an array of 2.5 micron holes. Air was drawn through the device at 70 LPM, and the aerosol was collected onto a filter or Andersen cascade impactor. The emitted dose was quantified from the filter collection data, and the particle size distribution was obtained from the best fit log-normal distribution to the impactor data. 57.0 +/- 5.9% of the dose of drug placed as an aqueous solution in the 45 microL collapsible container was delivered as an aerosol (n = 40). The best fit size distribution had an MMAD = (2.95 +/- 0.06) microns and a geometric standard deviation sigma g = 1.24 +/- 0.01 (n = 6). The AERX aerosol delivery system generates a nearly monodisperse aerosol with the properties required for efficient and repeatable drug delivery to the lung.