[CHARACTERISTICS OF BUDEFORU^® FOR BUDESONIDE AND FORMOTEROL MIXTURE]

Recently, BudeForu^® (BF), a generic of Symbicort Turbuhaler^® (SMB), is widely used in Japan. Although appearance of BF resembles to SMB, several differences in length, weight, and side-hole sizes are seen with precise inspection. As particle releases from the inhalation device is strongly influenced by its mechanical characteristics, we compared their particle release patterns.

An inhalation simulator generated either ramp-up or triangular (time to reach peak inhaling flow (PIF) = 0.42 s) inhalation pattern. Time trajectories of inhaled flow and released particles from either device were depicted with a photo-reflection method. Internal resistances of them were also measured.

Particle release patterns of both dry powder inhalers resembled each other. Immediately after release from the inhaler, they reached the peak value and then completed in 0.5 s. In either ramp-up or triangular inspiration pattern, a single burst developed at early inhalation. There were linear relationships between PIFs and emitted doses. The regression lines using ramp-up patters were: Y = 0.00241 X - 0.039, r² = 0.700, p ＜ 0.0001 (BF), Y = 0.00210 X - 0.038, r² = 0.654, p ＜ 0.0001 (SMB), and those using triangular patterns were: Y = 0.00223X － 0.0015, r² = 0.445, p ＜ 0.0001 (BF), and Y = 0.00229X － 0.0023, r² = 0.687, p ＜ 0.0001 (SMB). Internal resistances of the BF and SMB were 0.105±0.004 and 0.119±0.105 cmH₂O^0.5/L/min respectively.

Present experimental study suggested that aerodynamic characteristics of BF were quite similar to those of SMB.