Background: To improve dosing consistency and product features, budesonide inhalation powder delivered via a dry powder inhaler (DPI) (DPI-A 200 μg) was redesigned to include lactose, a newly shaped mouthpiece, and a new dose indicator (DPI-B). Budesonide DPI-B is available in two strengths (90 μg, 180 μg).Objective: To compare the relative rate and extent of the systemic availability of budesonide inhaled via DPI-A and DPI-B and test for systemic absorption bio equivalence.Methods: Adults (n = 37) with asthma as defined by the American Thoracic Society were randomized in an open-label, crossover, single-center, single-dose study to budesonide DPI-A 200 μg × 4 inhalations, budesonide DPI-B 180 μg × 4 inhalations, or budesonide DPI-B 90 μg × 8 inhalations, on 3 days, each separated by a washout period of ≥ 5 days. Plasma samples were collected immediately before and up to 12 h after dosing. Primary pharmacokinetic variables were area under the drug plasma concentration–time curve from 0 to infinity (AUC0–∞) and maximum plasma concentration (Cmax); plasma concentration at 12 h (C12h) and time to maximum plasma concentration (Tmax) were secondary variables. Treatments were considered bioequivalent if the 90% confidence intervals (CIs) for their AUC0–∞ and Cmax ratios fell between 80 and 125%. Adverse events were collected.Results: The 90% CIs for the ratios of AUC0–∞ and Cmax for budesonide DPI-A 200 μg and DPI-B 180 μg and for both budesonide DPI-B strengths fell between 80% and 125% (AUC0–∞ : budesonide DPI-B 180 μg × 4/DPI-A 200 μg × 4: 96.3% [90% CI: 90.9, 102.1]; budesonide DPI-B 180 μg × 4/DPI-B 90 μg × 8: 92.2% [90% CI: 87.0, 97.7]; Cmax: (budesonide DPI-B 180 μg × 4/DPI-A 200 μg × 4: 100.4% [95% CI: 92.1, 109.4]; budesonide DPI-B 180 μg × 4/DPI-B 90 μg × 8: 94.4% [90% CI: 86.6, 102.9]). No differences in C12h and Tmax were found between treatments. All treatments were well tolerated.Conclusions: Budesonide DPI-A 200 μg and DPI-B 180 μg have systemic absorption bioequivalence, and DPI-B 90 μg and 180 μg are dose-strength equivalent when administered at the same dose. These results may not be generalized to all patients with asthma, as this analysis included only patients with mild-to-moderate asthma aged ≥ 19 years. [ABSTRACT FROM AUTHOR]