Adapting the ICRP model to predict regional deposition of the pharmaceutical aerosols inhaled through DPIs and nebulizers

Using inhaler devices, drug delivery to the lung has been practiced for a long time to treat respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). The key question in this practice is how to deliver the drug to the regions of interest efficiently. Significant efforts have been made to develop models of depositional behavior of inhaled particles. The semi-experimental International Commission on Radiological Protection (ICRP) model is frequently used to predict depositional behavior of inhaled particles. Here, we have tried to adapt this model for predicting deposition of pharmaceutical particles that are inhaled through dry powder inhalers (DPIs) and nebulizers. We attempted to use a more proper extrathoracic deposition formula accounting for breath holding and bolus timing (in case of DPIs) and possible evaporation of droplets (in case of nebulizers). Two computer programs for DPIs and nebulizers were developed which can be freely accessed through e-mail contact to the first author.

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