An in vitro analysis of the output of salbutamol from different nebulizers

The objective of this study was to determine the particle size and mass output of salbutamol from different nebulizers used under simulated breathing conditions. Seven nebulizer/compressor combinations were assessed. Each nebulizer was charged with 5 mg salbutamol solution and connected to a breathing simulator operating at tidal volumes of 150 mL and 600 mL. Nebulizers were operated for 15 min. Salbutamol collected on the filters was measured by liquid chromatography. Aerosol particle size was determined separately by laser diffraction. The Pari LC Star nebulizer delivered the most salbutamol at both tidal volumes. The maximal output of the Medicaid Ventstream and Sidestream nebulizers was two-thirds that of the LC Star, and they delivered less salbutamol than the LC Star or LC Plus nebulizers. The Intersurgical Cirrus nebulizer delivered the least salbutamol at both tidal volumes, although there was only a small difference between the Cirrus and Ventstream or Sidestream nebulizers at 150 mL tidal volume. The LC Plus nebulizer produced larger particles, mass median diameter 5.3 microm, compared with 3.6-4.0 microm for the other nebulizers. In conclusion, there were large differences in the delivery of salbutamol between the nebulizers studied, even between nebulizers of apparently the same class, and this should be borne in mind by regulatory authorities, clinicians and researchers.