Sar-Gel Visualization of Inhaled Vapors in Human Nasal and Lung Casts - (Pages 1-9)
1Department of Aerospace and Mechanical Engineering, California Baptist University, Riverside, CA, 92504, USA; 2Department of Biomedical Engineering, California Baptist University, Riverside, CA, 92504, USA
Abstract: An accurate knowledge of drug distribution in human airways after drug administration is critical in establishing dose-response correlations and optimizing the treatment outcomes. However, human airways are inaccessible to conventional instruments, making it challenging to visualize and quantify local deposition within. This paper presented a simple but effective method to characterize local depositions in the human respiratory tract. Sar-Gel was used to visualize the deposition pattern and a colorimetry approach was developed to quantify the deposition fractions. Two examples were given, one being the nasal delivery and the other being pulmonary delivery. Anatomically accurate image-based model geometries were used in both examples. Computational modeling and simulations were also employed to cross-validate the corresponding in vitro tests. Results vividly show the variation of aerosol deposition distributions in response to different inhaler devices and breathing conditions. An excellent match was obtained in the surface deposition between in vitro tests and numerical simulations. The empirical colorimetry method slightly underestimated the direct weighing method but agreed well in the deposition trend. The Sar-Gel visualization approach in sectional respiratory tract casts seems to be a simple and effective way to characterize local vapor deposition. Sar-Gel visualization and numerical simulations can be complementary to each other in assessing device performance and optimizing inhalation drug deliveries.
Keywords: Sar-Gel visualization, aerosol deposition distribution, nebulizer, nasal drug delivery, pulmonary delivery.