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

Background: Inhaled corticosteroids are increasingly used in the treatment of asthma, and many different nebulizers are available to aerosolize steroi d medications. There are few comparative data on their ability to do so. Objective: Our purpose was to determine the particle size and mass output o f budesonide nebulizer suspension from different nebulizers. Methods: In vitro measurement of drug particle size and total drug output f rom 3 nebulizers (the Pari LC Plus, the Prtri LC Star, and the Medicaid Ven tstream) was performed under simulated breathing conditions. Nebulizers wer e charged with 2 mt (500 mu g) of budesonide suspension. A sinus pump a as used to draw aerosol from the nebulizers onto a filter during simulated ins piration at tidal volumes of 150 and 600 mt, mimicking pediatric and adult use. Aerosol particle size was determined separately by inertial impaction. Results: The LC Plus nebulizer had the highest initial output rate and deli vered the most budesonide at both breathing patterns. The maximal output ra tes of the Ventstream and LC Star nebulizers was half that of the LC Plus, but the LC Star nebulizer continued nebulization for longer and delivered t wice as much budesonide as the Ventstream did. However, the Ventstream prod uced the smallest particles, mass median diameter 3.1 mu m compared with 3. 8 mu m for the LC Star and 4.1 mu m for the LC Plus. Conclusions: This study has identified differences among the nebulizers tha t would not have been apparent with current standards for nebulizer assessm ent. Incorporation of breathing simulation in the study imitates patient us e and allows effective nebulization times to be predicted. The results sugg est that the nebulizers studied would deliver different masses of budesonid e to the lungs and to the upper airway. This may have important consequence s in determining the efficacy and side effect profile of budesonide.