In vitro nasal powder deposition studies: Alberta Idealized Nasal Inlet compared to Realistic Nasal Cast

Loco-regional nasal delivery could represent a targeted approach for administering different drugs, such as antivirals, to the upper respiratory tract. Many factors influence the delivery of therapeutics via nasal devices and consequently various in vitro nasal models have been employed as tools to predict the in vivo deposition behaviour. In this study, the nasal regional deposition of a favipiravir dry powder by means of Turbospin® dry powder device was evaluated at two different air flow rates in two different nasal models: one realistic model (in-house 3D printed Nasal Cast) and one idealised model (Alberta Idealized Nasal Inlet, AINI, Copley Scientific, UK). The deposition studies in both nasal models reveal the suitability of Turbospin® device as a breath intake nasal dry powder inhaler at both basal (15 L/min) and sharp (34 L/min) air flow inspiration conditions. However, when comparing the two nasal models, differences in deposition were observed, particularly in the nostrils and posterior regions. These differences have been caused by variations in the powder's adherence to the nasal areas (different nasal models’ materials and surface area of the models): different coatings and set-up conditions should be further investigated.