Mechanical factors affecting nebulized albuterol aerosol particle sizes for asthma drug delivery

Nebulized particles must have diameters between 1 to 5 μm (optimal particle size range [OPSR]) to be deposited in the lower respiratory tract. The purpose of this study is to determine factors that affect the particle size distributions of nebulized albuterol.

We used a sophisticated laser diffraction machine to measure aerosol particle size distributions. We compared the percentage of particles in the OPSR at different flow rates through single-use disposable (SUD) and semipermanent nebulizers at different flow rates under different conditions.

The SUD nebulizer produced OPSR percentages of 16%, 28%, 40%, 50%, 56%, and 62% at 3, 4, 5, 6, 7, and 8 Liters per minute (Lpm), respectively. The semipermanent nebulizer, however, produced OPSR percentages of 57%, 57%, 60%, and 64% at 3, 4, 5, and 6 Lpm, respectively. The home pump produced a gas flow rate of 5.2 Lpm through the SUD nebulizer and 4.2 Lpm through the semipermanent nebulizer. Single-use disposable nebulizer performance did not degrade with use up to 150 nebulizations. Optimal particle size range percentages did not change significantly with large or small nebulization volumes.

Single-use disposable nebulizers do not degrade with use, but their performance is highly dependent on gas flow rates. At the flow rate achieved by the home pump, the semipermanent nebulizer performs better than the SUD nebulizer.