In this study, subjects were randomized were randomized to either nicotine replacement patches or ENDs. In order to maintain the blind, subjects used both the nicotine replacement patches and the ENDS device. Subjects were requested not to smoke, but the number of regular cigarettes used were collected. Subject were seen every day for 15 days, The nicotine patch was applied at rotating sites, and the ENDS cartridge was replaced every day. The cartridge was weight when dispended and upon return. On days, 1, 5, 10 subjects remained in the clinic for 4 hours for collection of biomarkers. On these days, a new ENDS cartridge device was inserted and then used for 10 minutes, and then not used for 4 hours. A new cartridge was insert at the end of 4 hours. The patch was applied prior to using the ENDS device on these days.
The SU domain was used to represent the number of cigarettes used, but is not shown.
EC was used to represent the collected exposure data since a double dummy design was used. The EX domain was used to represent the subject's exposure to the product contain nicotine.