Ribavirin Administration by Inhalation: Aerosol-Generation Factors Controlling Drug Delivery to the Lung

We determined output characteristics (aerosol size and concentration) as a function of time of the Small Particle Aerosol Generator (SPAG-2, 6000 series), which is supplied for use with ribavirin. METHOD: We measured particle size by cascade impactor and aerosol concentration by spectrophotometric analysis. RESULTS: Aerosol concentrations and particle sizes increased with time, especially during prolonged periods of aerosol generation. Aerosolized drug concentrations in a typical administration hood were within 5% of those emitted by the generator unless the hood was placed in a draft, which caused the loss of significant aerosol. Changes in aerosol concentration and total output occurred when either airflows or reservoir volumes were changed. CONCLUSION: Every effort should be made to sustain maximum respirable concentrations by paying close attention to the aerosol delivery system and its operating conditions.