Output and aerosol properties of 5 nebulizer/compressor systems with arformoterol inhalation solution

Arformoterol, the (R,R) isomer of formoterol, is approved as an inhalation solution for the treatment of bronchoconstriction in patients with chronic obstructive pulmonary disease. Multiple nebulizer systems are commercially available. Different nebulizers can differ significantly in drug output, which may impact drug delivery and clinical efficacy. This study compared the aerosol properties of arformoterol delivered via 5 commonly used nebulizer systems for the home-care market.

The delivered dose of arformoterol inhalation solution (15 microg/2 mL) was collected in a glass Dreschel-type apparatus. The delivered amount in fine-droplet fraction was assessed with an Andersen cascade impactor, and droplet size (average median diameter and average percent<5 microm) was evaluated via laser diffraction. Compressor flow rate measurements were taken after 1 min and 6 min by placing the flow meter in line with each system.

The Pari LC Plus, Updraft II Opti-Neb, and NebuTech systems delivered similar amounts of the 15-microg nominal dose (from 23% to 25%). The Pari LC Star and Sidestream systems delivered slightly higher doses (31% and 35%, respectively). The nebulizer/compressor systems differed somewhat with respect to droplet size. The NebuTech delivered the lowest fine-droplet fraction (61%) via Andersen cascade impactor, and the smallest percent of droplets<5 microm (40%) via laser diffraction. The Pari LC Star and Sidestream delivered the highest fine-droplet fraction (100% and 93%, respectively), and the greatest percent of droplets<5 microm (84% and 88%). The fine-droplet fractions for the Updraft II Opti-Neb and Pari LC Plus were 93% and 89%, respectively, and the percent of droplets<5 microm was about 67%. Compressor flow rates ranged from 3.2 L/min (Pari LC Plus) to 5.4 L/min (NebuTech).

The results of this study demonstrate that the choice of nebulizer/compressor system can influence the aerosol properties of arformoterol inhalation solution and should be considered when prescribing nebulized medications.