A study of drug aerosols generated by various devices for inhaled steroids

PURPOSE: To evaluate the performances of various devices for inhaled steroid. METHODS: Aerosol particle diameters were determined using the Aerodynamic Particle Sizer Spectrometer. Conversion ratios to fine particle aerosol were determined using an Andersen non-bubble sampler. RESULTS: The mass median aerodynamic diameter was between 1 and 4 microm for all devices examined, tending to decrease with the increase in a suction flow rate. The percent of drug aerosolized less than 11 microm in diameter at a suction flow rate of 28.3 L/min was 100% for BDP-HFA and CIC-HFA, 87.5% for FP-HFA, 47.0% for BUD-DPI, 6.2% for FP-DPI, and 4.9% for SFC-DPI. The percent of drug aerosolized less than 7.6 microm in diameter at a suction flow rate of 60 L/min was 78.2% for BUD-DPI, 5.9% for FP-DPI, and 6.5% for SFC-DPI. DISCUSSION: For MDI preparations, devices permitting easy synchronization of drug atomization and inspiration exhibited higher inhalation efficiency. For DPI preparations, the BUD-DPI device exhibited higher inhalation efficiency, which was enhanced by increasing the suction flow rate.