Efficiency of Pulmonary Administration of Tobramycin Solution for Inhalation in Cystic Fibrosis Using an Improved Drug Delivery System

Abstract

To determine whether tobramycin solution for inhalation (TSI) can be administered safely and more efficiently with a new-generation aerosol device, the AeroDose 5.5 RP inhaler (Aerogen; Mountain View, CA) than with the approved PARI LC PLUS nebulizer (PARI Respiratory Equipment; Monterey, CA) with Pulmo-Aide compressor (DeVilbiss Corp; Somerset, PA). Second, we wanted to ascertain which AeroDose-delivered tobramycin dose is equivalent to the standard 300-mg dose administered with the PARI LC PLUS. Open-label, randomized, multicenter, single-dose, three-period, four-treatment, active- control, crossover trial. Nine US cystic fibrosis (CF) centers. Fifty-three patients >or= 12 years of age with a confirmed diagnosis of CF, the ability to expectorate sputum, and FEV(1) of >or= 40% of predicted. Subjects inhaled three single doses of TSI at 1-week intervals, as follows: conventional control treatment, 300 mg via the PARI LC PLUS; and two of three experimental treatments, 30, 60, or 90 mg via the AeroDose. FEV(1) was measured before and after dosing. After each dose, sputum and serum samples were collected at various intervals for 8 h, and urine was collected for 24 h to estimate lung and systemic tobramycin delivery. There were no significant differences between treatments in the change in FEV(1) 30 min after dosing or in the frequency of adverse events. Sputum and serum levels of tobramycin produced by the AeroDose 90-mg dose treatment approximated those achieved with the PARI LC PLUS 300-mg dose treatment. Nebulization times using the AeroDose inhaler were < 50% those of the PARI LC PLUS. Compared with the standard nebulizer, the AeroDose safely achieved an approximately threefold greater efficiency in the delivery of TSI to the lungs in less than half the time.