Simulations of the Deposition of Pharmaceutical Aerosols in the Human Respiratory Tract by Dry Powder Inhalers (Dpis)

Investigation of pharmaceutical aerosol deposition in the human respiratory tract is an important topic because it enhances knowledge regarding the effective treatment of lung diseases. Herein, deposition in the human respiratory tract produced by the use of Dry Powder Inhalers (DPIs) was modeled for an adult male. A modified version of the model named Exposure Dose Model 2 (ExDoM2) was used where simulations incorporated both monodisperse and polydisperse aerosols. The impact of breath holding and mouthpiece diameter was also examined. The results revealed that the larger the aerodynamic diameter, the greater the deposition in the extrathoracic region. On the contrary, higher deposition of polydisperse particles in the tracheobronchial and alveolar-interstitial region was observed for particles with aerodynamic diameter 2-4 mu m. In the extrathoracic region, deposition increased with a decrease in the mouthpiece diameter. However, its effect is negligible for particles approximately <1 mu m in the tracheobronchial and alveolar-interstitial regions. For bigger particles, an increase in mouthpiece diameter resulted in an increase of the deposition. Similar findings were obtained for monodisperse particles. In addition, the results showed that breath holding increases the deposition in the lungs for all mouthpiece diameters and Mass Median Aerodynamic Diameters (MMADs), which confirms the medical recommendations of breath holding after inhalation of pharmaceutical aerosols through DPIs for more effective treatment of lung diseases. Finally, the user of the modified version of ExDoM2 has the capability to modify the parameters of the model for a more representative/realistic scenario. Future objectives include simulations that adopt the effect of particle properties (density and shape factor) and other parameters (such as the tidal volume), as well as simulations incorporating deposition using realistic input data (MMAD and standard deviation s(g)).