An insight into the aerosolization pattern of formoterol fumarate dry powder inhalation formulation actuated via two different inhaler devices

Abstract

Purpose: Effective inhaled drug delivery is essential for managing bronchial asthma and chronic obstructive pulmonary disease (COPD). This study compared the aerosolization efficiency of two different dry powder inhalers (DPIs), the Aerolizer and Revolizer, using a fixed formulation of formoterol fumarate. Methods: Aerodynamic particle size distribution was measured using a next-generation impactor (NGI), and delivered dose uniformity was assessed with a dosage unit sampling apparatus (DUSA), both at a fixed flow rate of 60 L/min. Drug content was quantified using a validated high-performance liquid chromatography (HPLC) method, and performance metrics were analyzed using CITDAS software. Data were averaged (mean ± SD) and compared by statistical tests (e.g., ANOVA or t-tests), with p<0.05 indicating significance. Results: The Aerolizer achieved a fine particle dose (FPD) of 4.71 µg, which was 2.39 times higher than that of the Revolizer (1.97 µg). It also delivered approximately 20% greater overall dose and showed more consistent deposition in the NGI stages. While both devices demonstrated similar fine particle fractions (FPF), the difference in FPD was primarily due to the higher emitted dose from the Aerolizer. The use of a fixed flow rate allowed direct comparison of device performance. Conclusion: These findings highlight the significant influence of device design on DPI performance, even when the formulation remains constant. The Aerolizer, a low-resistance inhaler, showed superior delivery efficiency than the Revolizer under standardized conditions. Future studies should include pressure-drop–adjusted or patient-simulated testing to better reflect clinical inhalation profiles and further explore how device mechanics influence drug delivery.

Keywords: Aerolizer, Formoterol fumarate, Inhaler, Next Generation Impactor, REvolizer, Dry powder inhaler