Determining the Effect of Age and Head Position on Aerosol Delivery to Turbinate Regions of Human Intranasal Airways

JANA KESAVAN, Kristina Kuypers, Douglas Sommerville, Beth Laube, US ARMY DEVCOM CBC, Aberdeen Proving Ground, Maryland

     Abstract Number: 4
     Working Group: Health-Related Aerosols

Abstract
Many drugs are delivered intranasally to adults and children. However, little is known of the effect of age and head position on aerosol delivery to the turbinate regions. This study quantified turbinate deposition in anatomically correct models of the intranasal airways of an 18 year old male, a 5-year-old male and a 2-year-old female, constructed with 3D-printing technology. Each model consisted of a face with nostrils plus top, middle and bottom sections that contained superior, middle and inferior turbinates, respectively. Each model was tested 6 times sitting with head tilted back at 45 degrees (sitting45), supine, and supine with head tilted back at 45 degrees (supine45). Aerosol was delivered through a mucosal atomization device (MAD^TM) attached to a one mL syringe. There was no air flow through the model. Syringes were filled with 0.25mL of 0.9% sodium chloride solution mixed with fluorescein. Following aerosol administration, model sections were individually rinsed in water and samples tested for fluorescence using a fluorometer. The amount of fluorescence in each sample represented the amount of aerosol deposited in each section and was expressed as a percent of fluorescence detected in a reference sample. For the 18 and 5-year-old models, deposition to the superior turbinate was optimized in the supine45 position and to the inferior turbinate in the supine, or sitting45 positions. Deposition to the middle turbinate was similar for the three positions. In contrast, for the 2-year-old model, deposition to the superior turbinate was similar for the three positions, whereas, deposition to the inferior turbinate was optimized in the sitting45 position and to the middle turbinate in the supine45 position. These results show that both age and head position play a major role in aerosol delivery to human nasal turbinate regions, using the MAD^TM delivery device.