Participants
asthma, urticaria
AIDS, ASTHMA, URTICARIA
Potential participants attended a screening visit, and 32 healthy male or female participants who met the inclusion criteria were enrolled in the study to ensure that a minimum of 24 participants completed the study. Participants were 21–65 years of age, inclusive, and were generally healthy as determined by clinical laboratory and physical evaluations including haematology, clinical chemistry, urinalysis, serology, urine drug and alcohol screen, medical history, physical examination, lung function tests, vital signs assessment and 12-lead ECG. All participants had at least a one year history of cigarette smoking and e-cigarette use and were current dual users of combustible cigarettes (smoking ≥ 6 mg ISO tar cigarettes and a maximum of 21 per week) and e-cigarettes (regular use of e-cigarettes with an e-liquid nicotine strength of at least 18 mg/ml). A urine cotinine threshold of ≥ 200 ng/ml was used to confirm nicotine product use status. For female participants, a negative serum pregnancy test at screening and a urine pregnancy test at check-in to the clinical site was required. Women of childbearing potential were required to use an accepted form of contraception during and for 30 days after the study.The main exclusion criteria were pregnancy or breastfeeding (women only); self-reported non-inhalation of cigarette smoke/e-cigarette vapour; participants who did not use a flavoured e-liquid (since a flavoured e-liquid was used in the study); significant history of urticaria or asthma; blood donation of ≥ 450 ml within the three months before the participant’s first study visit, or plasma donation in the seven days prior to screening, or platelets donation in the six weeks prior to screening; participants who are planning to quit smoking or e-cigarette use; or use of any medication or substance that aids smoking cessation in the 30 days prior to the study.