Particle size and small airway effects of mometasone furoate delivered by dry powder inhaler

Inhaled corticosteroids administered by dry powder inhaler (DPI) or metered-dose inhaler are potent anti-inflammatory agents recommended for management of persistent asthma. Respiratory pharmacotherapy is unique in that proper delivery of the medication can be as important as the medication that is delivered. This study was designed to assess the mass median aerodynamic diameter (MMAD) of mometasone furoate (MF) particles from the 100- and 200-microgram/inhalation strength Twisthhaler (Merck & Co., Inc., Whitehouse Station, NJ) and to examine clinical effects of MF-DPI on midexpiratory flow. The MMAD with 100- and 200-microgram Twisthaler inhalers was analyzed using an Anderson cascade impactor. Clinical trial data for MF-DPI administered q.d. in the evening (P.M.) in adults and adolescents aged ≥12 years, as well as children aged 4‐11 years, were examined post hoc for changes in forced expiratory flow between 25 and 75% of vital capacity (FEF_25‐75). The average MMAD of the 100-microgram strength Twisthaler (n = 24) was 2.0 micrometers; the average MMAD of the 200-microgram strength Twisthaler (n = 24) was 2.2 micrometers. In adults and adolescents (n = 1149), significant improvements in FEF_25‐75 occurred with MF-DPI administered q.d. P.M. versus placebo (p ≤ 0.05). In children (n = 296), FEF_25‐75 improved significantly with MF-DPI at 100 microgram q.d. P.M. versus placebo at day 4 and every visit thereafter (p ≤ 0.05). In vitro study suggests that the particle size of MF is optimal (∼2 micrometers) for efficient lung deposition when administered via the Twisthaler. Furthermore, randomized, controlled trials provide clinical evidence that MF-DPI q.d. treatment improves small airway function in patients with mild persistent or moderate asthma.