AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Characterization of Air-Liquid-Interface (ALI) in vitro Exposure Systems for E-vapor Aerosol Applications
JINGJIE ZHANG, Michael Oldham, Russell Wolz, Pavel Kosachevsky, Utkarsh Doshi, I. Gene Gilman, Kyeonghee Lee, Altria Client Services LLC
Abstract Number: 186 Working Group: From Aerosol Dosimetry and Toxicology to Health
Abstract Direct delivery of aerosol or vapor to the apical surface of cells (ALI) allows clinically relevant exposure for in vitro toxicological evaluation of inhalable chemicals. However, dose assessment in the ALI exposure system remains a challenge, especially for evolving aerosols such as e-vapor. In this study, we quantitatively characterized the aerosol delivery in commercially available ALI in vitro exposure systems (Vitrocell® Ames 48 (Ames 48) and Vitrocell® 24/48 (VC 24/48)) for e-vapor applications.
A cig-a-like test cartridge filled with a prototype e-liquid containing propylene glycol, glycerin, nicotine and water was used to generate e-vapor aerosols using a Vitrocell® 1/7 puffing machine. Aerosol size distribution, mass deposition, and effective delivery to the exposure inserts (i.e. the petri dish in the Ames 48 or transwells in the VC 24/48 ) were measured for both Ames 48 and VC 24/48 systems with the regular aerosol delivering method per manufacturer’s instructions. Results showed that 1) the MMAD of the delivered aerosol was below 1.5 µm with the GSD between 1.8 to 2.1 as measured with a cascade impactor; 2) aerosol delivery in the exposure inserts increased linearly with the puff number; and 3) there was about 30% loss of aerosol mass in the aerosol transportation path prior to entry into the exposure system. To minimize aerosol loss, we revised the aerosol delivering method by shortening the transportation path and showed that 1) the aerosol loss prior to the exposure system was reduced to ~10%; 2) aerosol delivery to the exposure inserts was increased up to 3 fold compared to that of the regular delivery method. Aerosol chemistry was also analyzed. The methods developed in this study can be applied to standardize the ALI aerosol characterization of e-vapor products.