Determination of emitted particle characteristics and upper airway deposition of Symbicort® Turbuhaler® dry powder inhaler

The mass median aerodynamic diameter (MMAD) of the particle ensemble released from Symbicort® Turbuhaler® dry powder inhaler and the aerosol particle volume size distribution in a realistic upper airway was studied experimentally, assuming different inhalation waveforms. The idealized waveforms were determined from the breathing parameters of 25 healthy voluntary adults who inhaled through a not activated Turbuhaler® device.The amount of particles available for lung deposition was quantified by numerical simulations with the help of the stochastic lung deposition model (SLDM). It was calculated that approximately 30% of the particles released from the DPI are deposited in the upper airway. The lung deposition of the drug from the DPI was calculated to be between 16% and 59% of the nominal dose. The peak inhalation flow and the inhalation volume were found to be the main factors affecting the efficiency of the deposition, the inhalation time has also a small effect on it. The deposition of the Symbicort® Turbuhaler® in the lung as a function of tin and PIF. [Display omitted]