Systemic availability and lung deposition of budesonide via three different nebulizers in adults

Background: Budesonide is an inhaled corticosteroid widely used in the treatment of asthma. The local and systemic availability of budesonide has been determined in adults via pressurized metered-dose inhaler and dry-powder inhaler. Objective: To estimate lung deposition and systemic availability of budesonide inhalation suspension in healthy adults. Methods: Twelve adult volunteers entered an open, randomized, five-way crossover study and received the following treatments, with 1-week washout between treatments: separate 2-mg (nominal dose) budesonide doses via the Pari Inhalierboy (Inhalierboy; Pari GmbH, Starnberg, Germany), Pari LC Jet Plus (Jet Plus, Pari GmbH), and Maxin MA-2 (MA-2; Clinova Medical AB, Malmo, Sweden) jet nebulizers, 4 mg budesonide orally, and 0.5 mg budesonide intravenously. The plasma concentration of budesonide was measured up to 8 hours postadministration. Lung deposition and systemic availability of nebulized budesonide were estimated using pharmacokinetic evaluation. Results: In this first study of the bioavailability of budesonide inhalation suspension in adults, there were no differences between nebulizers in lung deposition (14 to 16%) or systemic availability (15 to 17%) relative to the nominal budesonide dose. Relative to the actual dose inhaled (dose-to-subject), lung deposition and systemic availability were statistically significantly higher for the Jet Plus (58 and 63%, respectively) and MA-2 (59 and 64%, respectively) nebulizers than the Inhalierboy (36 and 44%, respectively). The Inhalierboy produced larger aerosol droplets than Jet Plus or MA-2 nebulizers (7-, 5-, and 3-mum mass median diameters, respectively) and delivered a higher dose-to-subject than the other two nebulizers. Conclusion: Relative to the nominal dose, lung deposition and systemic availability of budesonide were similar via the three nebulizers tested.