Aerosol delivery of recombinant human DNase I: in vitro comparison of a vibrating-mesh nebulizer with a jet nebulizer.

BACKGROUND Inhaled recombinant human DNase I (rhDNase) improves clearance of visco-elastic secretions in patients with cystic fibrosis. Because of their portability, newer-generation vibrating-mesh nebulizers offer greater convenience for the patient, but their efficiency in delivering rhDNase has not been determined. METHODS We compared a newer-generation vibrating-mesh nebulizer (Omron MicroAir) to a Pari LC+ with the Pari ProNeb Ultra compressor (a commonly employed rhDNase administration system). With the Next Generation Pharmaceutical Impactor, we determined aerosol particle distribution. We also measured mass output efficiency, nebulization time, and mass of rhDNase that deposited on a filter during simulated breathing. RESULTS The mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) of aerosol from the MicroAir (MMAD 4.3 microm, GSD 2.8 microm) was equivalent to that from the Pari LC+ (MMAD 4.2 microm, GSD 2.7 microm). During simulated breathing the MicroAir had a higher total mass output efficiency (88%) than the Pari LC+ (68%) (P < .001), and total nebulization time was shorter with the MicroAir (6.1 min vs 7.2 min, P = .03). When nebulized to dryness, the mass of rhDNase delivered to the filter was comparable with the MicroAir (1.30 +/- 0.4 mg) and Pari LC+ (1.21 +/- 0.05 mg). CONCLUSION The MicroAir could be employed as a portable nebulizer for rhDNase therapy in patients with cystic fibrosis.