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

To evaluate the performances of various devices for inhaled steroid.

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.

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.

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.