Effective delivery of particles with the HandiHaler (R) dry powder inhalation system over a range of chronic obstructive pulmonary disease severity

The HandiHaler((R)) is a dry powder breath activated inhaler system develop ed for inhalation therapy for patients with airway disease. Its operation i s based on the evacuation of powder from a pierced capsule. We sought to do cument the inspiratory flow rates attained by patients inspiring through th e HandiHaler((R)) with various degrees of airflow limitation. Subjects with stable chronic obstructive pulmonary disease (COPD) were the study's popul ation. An in vitro study of fine particle dose was conducted using an Ander sen Cascade Impactor to assess medication delivery at low inspiratory flow rates. Subsequently, an in vivo study was conducted to determine inspirator y flow rates in patients with COPD as measured through a pneumotach with a custom coupler device with and without the HandiHaler (R). Patients were cl assified into three approximately equal groups of spirometric severity rang ing from mild (46-65% predicted normal forced expiratory volume in 1 sec [F EV1]), to moderate (28-45%) to severe (less than or equal to 27%). The in v itro study indicated delivery of medication at flow rates as low as 20 L/mi n. Twenty-six men completed the in vivo study (age 66.9 +/- 10.9 years, FEV 1 = 1.02 +/- 0.45 1.). The median peak inspiratory flow rates attained in t he mild (n = 8), moderate (n = 10), and severe (n = 8) categories were 45, 45.6, and 35.4 L/min respectively. The minimum peak inspiratory flow rates in the three groups were 28.2, 21.6 and 20.4 L/min. The HandiHaler((R)) dev ice effectively delivers particles to the lung over a wide range of airflow limitation in patients with COPD.