Nicotine VapingNCT05430334
Assess the Influence of Nicotine Flux and Nicotine Form on Subjective Effects Related to Dependency
A study testing e-liquid 1, e-liquid 2 and e-liquid 3 in people with Nicotine Vaping and Nicotine Dependence, run by American University of Beirut Medical Center at 1 site in Lebanon.
Trial summary
Electronic nicotine delivery systems (ENDS) heat and vaporize a nicotine-containing liquid to produce an aerosol that can deliver nicotine to the blood and the brain. ENDS use has increased rapidly in the last decade, especially among youth: over 20% of US high school students are current ENDS users, and there is… Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Nicotine Vaping, Nicotine Dependence, Nicotine Addiction
- What is being tested?
- e-liquid 1, e-liquid 2 and e-liquid 3
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 142 participants
- Where
- 1 siteLebanon
- Study dates
- 13 Jul 2022to 11 Jul 2025
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Must be healthy and above 18 years of age
- Must be willing to provide informed consent, attend the lab, and abstain from tobacco/nicotine as required (participants will be instructed to abstain from nicotine/tobacco and/or ENDS use for ≥12h)
- A dual ENDS and tobacco user who reports daily use of ENDS (≥ 3 mg/ml nicotine) or cigarettes (any frequency) AND someday use (≥ 3 days/week) of ENDS (≥ 3 mg/ml nicotine) or cigarettes (any frequency) for the past 3 months or longer
Who cannot join
- History of chronic disease or an uncontrolled psychiatric condition
- History of or active cardiovascular disease, low/high blood pressure, seizures, regular use of a prescription medication (except vitamins/birth control)
- Past month use of cocaine, opioids, benzodiazepines, or methamphetamines
- Individuals who report using marijuana >15/30 days
- Women will be excluded if they are breast-feeding or pregnant
- Participants intending to quit tobacco/nicotine use in the next 30 days and referred to cessation treatment
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Nicotine Flux, a Potentially Powerful Tool for Regulating Nicotine Delivery From Electronic Cigarettes: Significance of Nicotine Flux to the Rate of Nicotine Delivery and Subjective Effect
Electronic nicotine delivery systems (ENDS) heat and vaporize a nicotine-containing liquid to produce an aerosol that can deliver nicotine to the blood and the brain. ENDS use has increased rapidly in the last decade, especially among youth: over 20% of US high school students are current ENDS users, and there is evidence of nicotine dependence in this population. Federal legislation has been proposed that would restrict ENDS liquid nicotine concentration to make ENDS "significantly less addictive and appealing to youth." However, these and other efforts to curb addiction by limiting nicotine liquid concentration are unlikely to succeed because nicotine emissions from ENDS depend on multiple variables. To achieve the intended public health aims, regulations targeting addiction must focus on nicotine delivery, not nicotine concentration. While nicotine delivery cannot be regulated directly, the rate at which an ENDS emits nicotine, the "nicotine flux", can be regulated and, importantly, predicted based on a few device design and operating variables. However, to date there is no empirical evidence demonstrating the relationship between flux and delivery, nor between flux and the subjective effects that support nicotine dependence. Closing this gap is essential for providing an effective framework for regulating ENDS. At the American University of Beirut, the investigators will assess the relationship between nicotine flux, form, and subjective effects. Participants will use ENDS devices with varying nicotine fluxes and forms. Dependency measures, such as urge to smoke, craving, and abstinence, will be assessed. The outcome will indicate the degree to which nicotine flux/form influence subjective effects related to dependency, puffing intensity, and exposure to toxicants. In summary, this project will provide the empirical evidence needed for public health agencies to use nicotine flux as an encompassing and convenient construct to regulate nicotine delivery from ENDS.
Read the detailed description
Assess the influence of nicotine flux and nicotine form on subjective effects. At AUB, the investigators will assess subjective effects (e.g. product liking, nicotine craving) and puffing topography for 130 participants who will undergo 5 ENDS use sessions (combinations 1-5) consisting of 2 bouts (10 puffs + 60min ad libitum) with 2 fluxes (15 and 35μg/s) x 2 forms (protonated, freebase) and a 0 nicotine condition. In addition, the investigators will use a state-of-the-art device to sample in situ a fraction of the aerosol generated during each puff to verify actual nicotine flux and form, and measure exposure to pulmonary toxicants (carbonyls). The investigators hypothesize that increasing nicotine flux and protonated nicotine will result in greater reductions of nicotine craving, and lower puffing intensity and carbonyl exposure. 10 of the participants that completed AIM 2 will be asked to attend our lab at AUB for one additional visit, where they will be assigned either a high flow or low flow ENDS. During the visit, participants will undertake three smoking bouts consisting of 10 puffs each, where they will be presented with alternating puffs of the assigned device in which a specific ENDS design variable is systematically varied between puffs. Puff topography, inhalation behavior, and subjective effects related to sensory feedback will be recorded. We hypothesize that power and liquid composition variations will result in immediate and reversible changes in puffing/inhalation behavior.
- Conditions
- Nicotine Vaping, Nicotine Dependence, Nicotine Addiction
- Being tested
- e-liquid 1, e-liquid 2, e-liquid 3, e-liquid 4, e-liquid 5
- Keywords
- Nicotine, Nicotine Flux, Vaping, ENDS, Aerosol, Combustible
- Medical subject headings
- Vaping, Tobacco Use Disorder
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
e-liquid 1Combination product
30/70 propylene glycol/vegetable glycerin ratio with nicotine concentration 4mg/ml protonated
e-liquid 2Combination product
30/70 PG/VG ratio with nicotine concentration 10mg/ml protonated
e-liquid 3Combination product
30/70 PG/VG ratio with nicotine concentration 4mg/ml free base
e-liquid 4Combination product
30/70 PG/VG ratio with nicotine concentration 10mg/ml freebase
e-liquid 5Combination product
30/70 PG/VG ratio with nicotine concentration 0mg/ml (placebo)
e-liquid 6Combination product
30/70 PG/VG ratio with nicotine concentration 0mg/ml
e-liquid 7 and e-liquid 8Combination product
e-liquid 7: 30/70 PG/VG ratio with nicotine concentration 4mg/ml protonated e-liquid 8: 30/70 PG/VG ratio with nicotine concentration 8mg/ml protonated
e-liquid 9 and e-liquid 10Combination product
e-liquid 9: 30/70 PG/VG ratio with nicotine concentration 4mg/ml protonated e-liquid 10: 70/30 PG/VG ratio with nicotine concentration 4mg/ml protonated
| Study group | Role | What they receive |
|---|---|---|
| Combination One - 15μg/s protonated nicotine flux | Experimental | The investigators will test the subjective effects of nicotine flux (15μg/s) coupled with one ratio of nicotine form (100% protonated). Following a one-hour observation period, participants will use Subox Mini C in a 10-puff directed (30sec inter-puff interval) bout. One hour after the first bout, participants will be instructed to puff on the device for 60-min ad libitum. Subjective measures (i.e., nicotine dependence, drug effects, product liking, and craving) will be administered 5 times/session: 5 min before and 5 min after onset of the directed bout and 5 min before, halfway into and 5 min after onset of the ad libitum bout. Receives: Combination Product: e-liquid 1 |
| Combination Two - 35μg/s protonated nicotine flux | Experimental | The investigators will test the subjective effects of nicotine flux (35μg/s) coupled with one ratio of nicotine form (100% protonated). Following a one-hour observation period, participants will use Subox Mini C in a 10-puff directed (30sec inter-puff interval) bout. One hour after the first bout, participants will be instructed to puff on the device for 60-min ad libitum. Subjective measures (i.e., nicotine dependence, drug effects, product liking, and craving) will be administered 5 times/session: 5 min before and 5 min after onset of the directed bout and 5 min before, halfway into and 5 min after onset of the ad libitum bout. Receives: Combination Product: e-liquid 2 |
| Combination Three - 15μg/s free base nicotine flux | Experimental | The investigators will test the subjective effects of nicotine flux (15μg/s) coupled with one ratio of nicotine form (100% free base). Following a one-hour observation period, participants will use Subox Mini C in a 10-puff directed (30sec inter-puff interval) bout. One hour after the first bout, participants will be instructed to puff on the device for 60-min ad libitum. Subjective measures (i.e., nicotine dependence, drug effects, product liking, and craving) will be administered 5 times/session: 5 min before and 5 min after onset of the directed bout and 5 min before, halfway into and 5 min after onset of the ad libitum bout. Receives: Combination Product: e-liquid 3 |
| Combination Four - 35μg/s free base nicotine flux | Experimental | The investigators will test the subjective effects of nicotine flux (35μg/s) coupled with one ratio of nicotine form (100% free base). Following a one-hour observation period, participants will use Subox Mini C in a 10-puff directed (30sec inter-puff interval) bout. One hour after the first bout, participants will be instructed to puff on the device for 60-min ad libitum. Subjective measures (i.e., nicotine dependence, drug effects, product liking, and craving) will be administered 5 times/session: 5 min before and 5 min after onset of the directed bout and 5 min before, halfway into and 5 min after onset of the ad libitum bout. Receives: Combination Product: e-liquid 4 |
| Placebo - Combination Five - 0μg/s nicotine flux | Placebo comparator | The investigators will test the subjective effects of nicotine flux (0μg/s) placebo. Following a one-hour observation period, participants will use Subox Mini C in a 10-puff directed (30sec inter-puff interval) bout. One hour after the first bout, participants will be instructed to puff on the device for 60-min ad libitum. Subjective measures (i.e., nicotine dependence, drug effects, product liking, and craving) will be administered 5 times/session: 5 min before and 5 min after onset of the directed bout and 5 min before, halfway into and 5 min after onset of the ad libitum bout. Receives: Combination Product: e-liquid 5 |
| Combination six - 0μg/s flux; high power/low power | Experimental | The investigators will test the subjective effects (perceived mouthful, perceived draw effort, and throat hit) at two power levels (20W and 40 W) with no nicotine in the liquid. Participants will alternate 10 directed puffs (30sec inter-puff interval) between two Subox Mini C devices differing only by the two power levels. Subjective measures will be administered following puff pairs 1\&2, 5\&6, and 9\&10. Receives: Combination Product: e-liquid 6 |
| Combination seven - 35μg/s flux; high power/low power | Experimental | The investigators will test the subjective effects (perceived mouthful, perceived draw effort, and throat hit) at two power levels (20W and 40 W) and a constant nicotine flux of 35 ug/s. Participants will alternate 10 directed puffs (30sec inter-puff interval) between two Subox Mini C devices (20 W; 8mg/ml and 40 W;4 mg/ml). Subjective measures will be administered following puff pairs 1\&2, 5\&6, and 9\&10. Receives: Combination Product: e-liquid 7 and e-liquid 8 |
| Combination eight - 15μg/s flux; high PG(propylene glycol)/VG(vegetable glycerin) / low PG/VG | Experimental | The investigators will test the subjective effects (perceived mouthful, perceived draw effort, and throat hit) at two propylene glycol/vegetable glycerin ratios (30/70 and 70/30). Participants will alternate 10 directed puffs (30sec inter-puff interval) between two Subox Mini C devices differing only by the two PG/VG ratios. Subjective measures will be administered following puff pairs 1\&2, 5\&6, and 9\&10. Receives: Combination Product: e-liquid 9 and e-liquid 10 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Subjective Effects - Strong Flavor (Combinations 1-5)
Strong flavor will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled magnitude scale (gLMS) on a subjective scale (0-10, No sensation - Strongest Imaginable), with higher scores indicating a stronger perceived flavor.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Harshness/Irritancy (Combinations 1-5)
Harshness/irritancy will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled magnitude scale (gLMS) on a subjective scale (0-10, No sensation - Strongest Imaginable), with higher scores indicating harsher/more irritating effects.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Throat Hit (Combinations 1-5)
Throat hit will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled magnitude scale (gLMS) on a subjective scale (0-10, No sensation - Strongest Imaginable), with higher scores indicating a stronger throat hit.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Overall Like: Flavor (Combinations 1-5)
Overall like: flavor will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled hedonic scale (LHS) on a subjective scale (0-10, most disliked - most liked), with higher scores indicating the flavor was liked more.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Overall Like: Harshness (Combinations 1-5)
Overall like: harshness will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled hedonic scale (LHS) on a subjective scale (0-10, most disliked - most liked), with higher scores indicating the harshness was liked more.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Overall Like: Throat Hit (Combinations 1-5)
Overall like: throat hit will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled hedonic scale (LHS) on a subjective scale (0-10, most disliked - most liked), with higher scores indicating the throat hit was liked more.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Overall Like: Warmth (Combinations 1-5)
Overall like: warmth will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled hedonic scale (LHS) on a subjective scale (0-10, most disliked - most liked), with higher scores indicating the warmth was liked more.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Satisfying (Combinations 1-5)
Satisfying will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating greater satisfaction.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Pleasant (Combinations 1-5)
Pleasant will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating greater pleasantness.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Taste Good (Combinations 1-5)
Taste good will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating better taste.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Calm (Combinations 1-5)
Calm will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating feeling calmer.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Concentrate (Combinations 1-5)
Concentrate will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating better ability to concentrate.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Awake (Combinations 1-5)
Awake will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating feeling more awake/alert.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Reduce Hunger (Combinations 1-5)
Reduce hunger will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating greater reduction in hunger.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Dizzy (Combinations 1-5)
Dizzy will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating greater dizziness.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Feeling Sick (Combinations 1-5)
Feeling sick will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating feeling more sick.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Want it Right Now (Combinations 1-5)
Want it right now will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating a stronger immediate desire for the product.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Smell (Combinations 1-5)
Smell will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating a stronger perceived smell. This item is drawn from the Electronic Cigarette Specific Effects Questionnaire, a modified/expanded version of the modified Cigarette Evaluation Questionnaire (mCEQ; Cappelleri et al., 2007) developed for ENDS. Participants rate the item on a 0-10 scale immediately following each bout. Item wording: 'Did the e-cig produce a smell?' (0 = not at all, 10 = extremely).
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Visible Vapor (Combinations 1-5)
Visible vapor will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating more visible vapor.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Importance Vapor (Combinations 1-5)
Importance vapor will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating vapor visibility mattered more to the participant. This item is drawn from the Electronic Cigarette Specific Effects Questionnaire, a modified/expanded version of the modified Cigarette Evaluation Questionnaire (mCEQ; Cappelleri et al., 2007) developed for ENDS. Participants rate the item on a 0-10 scale immediately following each bout. Item wording: 'Is the vapor/cloud of the e-cig important to you?' (0 = not at all, 10 = extremely).
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Subjective Effects - Puffs Similar (Combinations 1-5)
Puffs similar will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating the puffs were perceived as more similar to the participant's usual product.
Measured: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Smoking Urges - Brief Factor 1 (Intention/Desire)
Brief Factor 1 (Intention/Desire) will be assessed by the Questionnaire of Smoking Urges-Brief (QSU-Brief; Tiffany \& Drobes, 1991; Toll et al., 2006). Factor 1 is the sum of 6 items, each rated on a 0-10 scale (0=strongly disagree, 10=strongly agree), yielding a total score range of 0-60, with higher scores indicating stronger urges.
Measured: Assessed before and after the directed bout (Bout 1), and before, midway through, and after the ad libitum bout (Bout 2).
Smoking Urges - Brief Factor 2 (Relief of Neg. Affect)
Brief Factor 2 (Relief of Neg. Affect) will be assessed by the Questionnaire of Smoking Urges-Brief (QSU-Brief; Tiffany \& Drobes, 1991; Toll et al., 2006). Factor 2 is the sum of 4 items, each rated on a 0-10 scale (0=strongly disagree, 10=strongly agree), yielding a total score range of 0-40, with higher scores indicating stronger urges.
Measured: Assessed before and after the directed bout (Bout 1), and before, midway through, and after the ad libitum bout (Bout 2).
Withdrawal Symptoms - Minnesota Nicotine Withdrawal Scale (MNWS; Based on Hughes and Hatsukami, 1986)
The Minnesota Nicotine Withdrawal Scale (MNWS; based on Hughes and Hatsukami, 1986 questionnaire) was measured using composite mean of MNWS items (irritability, anxiety, difficulty concentrating, restlessness, hunger/appetite, Impatient, depression, desire for sweets and craving) on a 0-10 scale (Not at all - Extremely), with higher scores indicating greater withdrawal severity.
Measured: Assessed before and after the directed bout (Bout 1), and before, midway through, and after the ad libitum bout (Bout 2).
Secondary outcomes (11)
Puff Duration
Puff duration combination 1,2,3,4 \& 5
Measured: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Number of Puffs
Measured topography Total Number of Puffs (puffs).
Measured: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Puffing Time
Measured topography Average Puffing time (sec).
Measured: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Inter Puff Interval
Measured topography Average Inter Puff Interval (sec).
Measured: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Flow Rate
Measured topography Average Flow rate (Liters per minute: LPM).
Measured: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Mouth-level PM
Mouth-level PM (Particulate matter) dose estimated using the REALTIME real-time in-situ sampling device, which collects 5% of the aerosol at the mouthpiece during each puff; values are reported as the total session dose (5% fraction × 20), in mg.
Measured: Will be measured after the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Mouth-level Nicotine
Mouth-level nicotine dose estimated using the REALTIME real-time in-situ sampling device, which collects 5% of the aerosol at the mouthpiece during each puff; values are reported as the total session dose (5% fraction × 20), in mg.
Measured: Will be measured after the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Puff Duration - Combination 6,7 & 8
Measured topography Average Puff Duration (sec) - using Subox mini C. Puffs were administered in alternating order using block randomization; for Combination Six, odd puffs were delivered at 20W and even puffs at 40W; for Combination Seven, odd puffs were delivered at 20W/8mg/mL and even puffs at 40W/4mg/mL; for Combination Eight, odd puffs were delivered at 30/70 PG/VG and even puffs at 70/30 PG/VG.
Measured: Will be measured during the approximately 5-minute, 10-puff use bout
Sensory Feedback - Perceived Mouthful - Using Kangertech Subox Mini C (Sub-ohm Device)
The perceived mouthful will be assessed using the following question: "How would you rate the amount of smoke filling your mouth during the puff you just smoked?". A subjective visual analog scale will be used (1-5, barely any smoke- a lot of smoke) with higher scores indicating higher mouthful. Puffs were administered in alternating order using block randomization; for Combination Six, odd puffs were delivered at 20W and even puffs at 40W; for Combination Seven, odd puffs were delivered at 20W/8mg/mL and even puffs at 40W/4mg/mL; for Combination Eight, odd puffs were delivered at 30/70 PG/VG and even puffs at 70/30 PG/VG.
Measured: Will be measured during the approximately 5-minute, 10-puff use bout
Sensory Feedback - Perceived Draw Effort - Using Kangertech Subox Mini C (Sub-ohm Device)
The perceived draw effort will be assessed using the following question: " How would you rate the effort needed to draw the puff you just smoked?". A subjective visual analog scale will be used (1-5, easy- hard) with higher scores indicating harder draw effort. Puffs were administered in alternating order using block randomization; for Combination Six, odd puffs were delivered at 20W and even puffs at 40W; for Combination Seven, odd puffs were delivered at 20W/8mg/mL and even puffs at 40W/4mg/mL; for Combination Eight, odd puffs were delivered at 30/70 PG/VG and even puffs at 70/30 PG/VG.
Measured: Will be measured during the approximately 5-minute, 10-puff use bout
Sensory Feedback - Throat Hit - Using Kangertech Subox Mini C (Sub-ohm Device)
The perceived Throat hit will be assessed using the following question: "How would you describe the throat hit of the device you just used" (0-100 General Labeled Magnitude Scale; anchors: "barely detectable" to "strongest imaginable"). Puffs were administered in alternating order using block randomization; for Combination Six, odd puffs were delivered at 20W and even puffs at 40W; for Combination Seven, odd puffs were delivered at 20W/8mg/mL and even puffs at 40W/4mg/mL; for Combination Eight, odd puffs were delivered at 30/70 PG/VG and even puffs at 70/30 PG/VG.
Measured: Will be measured during the approximately 5-minute, 10-puff use bout
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Jun 2022
- Study start13 Jul 2022
- Primary completion11 Jul 2025
- Study completion11 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Nicotine VapingStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Each participant will attend the lab for five different visits that differ by nicotine flux and/or form in random order.
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 142 participants (actual)
Sponsor and investigators
- Lead sponsor
- American University of Beirut Medical Center
- Sponsor type
- University, hospital or other
- Collaborators
- National Institutes of Health (NIH), National Institute on Drug Abuse (NIDA)
- Responsible party
- Sponsor
- Investigators
- Soha Talih, PhD, Principal investigator, American University of Beirut Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05430334
- Sponsor's protocol ID
- American University Of Beirut
- Other IDs
- 1R01DA052565-01A1
- Status last verified
- Feb 2025
- First submitted
- 8 Jun 2022
- Last updated
- 18 Sep 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Participants data will not be available to other researchers
Publications
El-Hellani A, Hanna E, Sharma M, Blohowiak R, Joseph P, Eid T, Nadim H, El-Hage R, Salman R, Karaoghlanian N, Adeniji A, Salam S, Talih F, Elbejjani M, Breland A, Eissenberg T, Shihadeh A, Baldassarri SR, Talih S. Nicotine flux as a powerful tool for regulating nicotine delivery from e-cigarettes: Protocol of two complimentary randomized crossover clinical trials. PLoS One. 2023 Sep 21;18(9):e0291786. doi: 10.1371/journal.pone.0291786. eCollection 2023.
PubMed 37733666
Study at a glance
From the registry record, last updated by the sponsor on 18 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Nicotine Flux, a Potentially Powerful Tool for Regulating Nicotine Delivery From Electronic Cigarettes: Significance of Nicotine Flux to the Rate of Nicotine Delivery and Subjective Effect
- ClinicalTrials.gov ID
- NCT05430334
- Acronym / sponsor ID
- American University Of Beirut
- Conditions
- Nicotine Vaping, Nicotine Dependence, Nicotine Addiction
- Keywords
- Nicotine, Nicotine Flux, Vaping, ENDS, Aerosol, Combustible
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 142 participants (actual)
- Lead sponsor
- American University of Beirut Medical CenterUniversity, hospital or other
- Collaborators
- National Institutes of Health (NIH), National Institute on Drug Abuse (NIDA)
- Study start
- 13 Jul 2022 (actual)
- Primary completion
- 11 Jul 2025 (actual)
- Study completion
- 11 Jul 2025 (actual)
- First posted
- 24 Jun 2022 (actual)
- Results
- Posted 18 Sep 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Electronic nicotine delivery systems (ENDS) heat and vaporize a nicotine-containing liquid to produce an aerosol that can deliver nicotine to the blood and the brain. ENDS use has increased rapidly in the last decade, especially among youth: over 20% of US high school students are current ENDS users, and there is evidence of nicotine dependence in this population. Federal legislation has been proposed that would restrict ENDS liquid nicotine concentration to make ENDS "significantly less addictive and appealing to youth." However, these and other efforts to curb addiction by limiting nicotine liquid concentration are unlikely to succeed because nicotine emissions from ENDS depend on multiple variables. To achieve the intended public health aims, regulations targeting addiction must focus on nicotine delivery, not nicotine concentration. While nicotine delivery cannot be regulated directly, the rate at which an ENDS emits nicotine, the "nicotine flux", can be regulated and, importantly, predicted based on a few device design and operating variables. However, to date there is no empirical evidence demonstrating the relationship between flux and delivery, nor between flux and the subjective effects that support nicotine dependence. Closing this gap is essential for providing an effective framework for regulating ENDS. At the American University of Beirut, the investigators will assess the relationship between nicotine flux, form, and subjective effects. Participants will use ENDS devices with varying nicotine fluxes and forms. Dependency measures, such as urge to smoke, craving, and abstinence, will be assessed. The outcome will indicate the degree to which nicotine flux/form influence subjective effects related to dependency, puffing intensity, and exposure to toxicants. In summary, this project will provide the empirical evidence needed for public health agencies to use nicotine flux as an encompassing and convenient construct to regulate nicotine delivery from ENDS.
Detailed description
Assess the influence of nicotine flux and nicotine form on subjective effects. At AUB, the investigators will assess subjective effects (e.g. product liking, nicotine craving) and puffing topography for 130 participants who will undergo 5 ENDS use sessions (combinations 1-5) consisting of 2 bouts (10 puffs + 60min ad libitum) with 2 fluxes (15 and 35μg/s) x 2 forms (protonated, freebase) and a 0 nicotine condition. In addition, the investigators will use a state-of-the-art device to sample in situ a fraction of the aerosol generated during each puff to verify actual nicotine flux and form, and measure exposure to pulmonary toxicants (carbonyls). The investigators hypothesize that increasing nicotine flux and protonated nicotine will result in greater reductions of nicotine craving, and lower puffing intensity and carbonyl exposure. 10 of the participants that completed AIM 2 will be asked to attend our lab at AUB for one additional visit, where they will be assigned either a high flow or low flow ENDS. During the visit, participants will undertake three smoking bouts consisting of 10 puffs each, where they will be presented with alternating puffs of the assigned device in which a specific ENDS design variable is systematically varied between puffs. Puff topography, inhalation behavior, and subjective effects related to sensory feedback will be recorded. We hypothesize that power and liquid composition variations will result in immediate and reversible changes in puffing/inhalation behavior.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 8
- Model description
- Each participant will attend the lab for five different visits that differ by nicotine flux and/or form in random order.
| Arm | Type | Receives |
|---|---|---|
| Combination One - 15μg/s protonated nicotine flux | Experimental | Combination Product: e-liquid 1The investigators will test the subjective effects of nicotine flux (15μg/s) coupled with one ratio of nicotine form (100% protonated). Following a one-hour observation period, participants will use Subox Mini C in a 10-puff directed (30sec inter-puff interval) bout. One hour after the first bout, participants will be instructed to puff on the device for 60-min ad libitum. Subjective measures (i.e., nicotine dependence, drug effects, product liking, and craving) will be administered 5 times/session: 5 min before and 5 min after onset of the directed bout and 5 min before, halfway into and 5 min after onset of the ad libitum bout. |
| Combination Two - 35μg/s protonated nicotine flux | Experimental | Combination Product: e-liquid 2The investigators will test the subjective effects of nicotine flux (35μg/s) coupled with one ratio of nicotine form (100% protonated). Following a one-hour observation period, participants will use Subox Mini C in a 10-puff directed (30sec inter-puff interval) bout. One hour after the first bout, participants will be instructed to puff on the device for 60-min ad libitum. Subjective measures (i.e., nicotine dependence, drug effects, product liking, and craving) will be administered 5 times/session: 5 min before and 5 min after onset of the directed bout and 5 min before, halfway into and 5 min after onset of the ad libitum bout. |
| Combination Three - 15μg/s free base nicotine flux | Experimental | Combination Product: e-liquid 3The investigators will test the subjective effects of nicotine flux (15μg/s) coupled with one ratio of nicotine form (100% free base). Following a one-hour observation period, participants will use Subox Mini C in a 10-puff directed (30sec inter-puff interval) bout. One hour after the first bout, participants will be instructed to puff on the device for 60-min ad libitum. Subjective measures (i.e., nicotine dependence, drug effects, product liking, and craving) will be administered 5 times/session: 5 min before and 5 min after onset of the directed bout and 5 min before, halfway into and 5 min after onset of the ad libitum bout. |
| Combination Four - 35μg/s free base nicotine flux | Experimental | Combination Product: e-liquid 4The investigators will test the subjective effects of nicotine flux (35μg/s) coupled with one ratio of nicotine form (100% free base). Following a one-hour observation period, participants will use Subox Mini C in a 10-puff directed (30sec inter-puff interval) bout. One hour after the first bout, participants will be instructed to puff on the device for 60-min ad libitum. Subjective measures (i.e., nicotine dependence, drug effects, product liking, and craving) will be administered 5 times/session: 5 min before and 5 min after onset of the directed bout and 5 min before, halfway into and 5 min after onset of the ad libitum bout. |
| Placebo - Combination Five - 0μg/s nicotine flux | Placebo comparator | Combination Product: e-liquid 5The investigators will test the subjective effects of nicotine flux (0μg/s) placebo. Following a one-hour observation period, participants will use Subox Mini C in a 10-puff directed (30sec inter-puff interval) bout. One hour after the first bout, participants will be instructed to puff on the device for 60-min ad libitum. Subjective measures (i.e., nicotine dependence, drug effects, product liking, and craving) will be administered 5 times/session: 5 min before and 5 min after onset of the directed bout and 5 min before, halfway into and 5 min after onset of the ad libitum bout. |
| Combination six - 0μg/s flux; high power/low power | Experimental | Combination Product: e-liquid 6The investigators will test the subjective effects (perceived mouthful, perceived draw effort, and throat hit) at two power levels (20W and 40 W) with no nicotine in the liquid. Participants will alternate 10 directed puffs (30sec inter-puff interval) between two Subox Mini C devices differing only by the two power levels. Subjective measures will be administered following puff pairs 1\&2, 5\&6, and 9\&10. |
| Combination seven - 35μg/s flux; high power/low power | Experimental | Combination Product: e-liquid 7 and e-liquid 8The investigators will test the subjective effects (perceived mouthful, perceived draw effort, and throat hit) at two power levels (20W and 40 W) and a constant nicotine flux of 35 ug/s. Participants will alternate 10 directed puffs (30sec inter-puff interval) between two Subox Mini C devices (20 W; 8mg/ml and 40 W;4 mg/ml). Subjective measures will be administered following puff pairs 1\&2, 5\&6, and 9\&10. |
| Combination eight - 15μg/s flux; high PG(propylene glycol)/VG(vegetable glycerin) / low PG/VG | Experimental | Combination Product: e-liquid 9 and e-liquid 10The investigators will test the subjective effects (perceived mouthful, perceived draw effort, and throat hit) at two propylene glycol/vegetable glycerin ratios (30/70 and 70/30). Participants will alternate 10 directed puffs (30sec inter-puff interval) between two Subox Mini C devices differing only by the two PG/VG ratios. Subjective measures will be administered following puff pairs 1\&2, 5\&6, and 9\&10. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Must be healthy and above 18 years of age
- Must be willing to provide informed consent, attend the lab, and abstain from tobacco/nicotine as required (participants will be instructed to abstain from nicotine/tobacco and/or ENDS use for ≥12h)
- A dual ENDS and tobacco user who reports daily use of ENDS (≥ 3 mg/ml nicotine) or cigarettes (any frequency) AND someday use (≥ 3 days/week) of ENDS (≥ 3 mg/ml nicotine) or cigarettes (any frequency) for the past 3 months or longer
Key exclusion criteria (6 listed)
- History of chronic disease or an uncontrolled psychiatric condition
- History of or active cardiovascular disease, low/high blood pressure, seizures, regular use of a prescription medication (except vitamins/birth control)
- Past month use of cocaine, opioids, benzodiazepines, or methamphetamines
- Individuals who report using marijuana >15/30 days
- Women will be excluded if they are breast-feeding or pregnant
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| e-liquid 130/70 propylene glycol/vegetable glycerin ratio with nicotine concentration 4mg/ml protonated | Combination product | Combination One - 15μg/s protonated nicotine flux |
| e-liquid 230/70 PG/VG ratio with nicotine concentration 10mg/ml protonated | Combination product | Combination Two - 35μg/s protonated nicotine flux |
| e-liquid 330/70 PG/VG ratio with nicotine concentration 4mg/ml free base | Combination product | Combination Three - 15μg/s free base nicotine flux |
| e-liquid 430/70 PG/VG ratio with nicotine concentration 10mg/ml freebase | Combination product | Combination Four - 35μg/s free base nicotine flux |
| e-liquid 530/70 PG/VG ratio with nicotine concentration 0mg/ml (placebo) | Combination product | Placebo - Combination Five - 0μg/s nicotine flux |
| e-liquid 630/70 PG/VG ratio with nicotine concentration 0mg/ml | Combination product | Combination six - 0μg/s flux; high power/low power |
| e-liquid 7 and e-liquid 8e-liquid 7: 30/70 PG/VG ratio with nicotine concentration 4mg/ml protonated e-liquid 8: 30/70 PG/VG ratio with nicotine concentration 8mg/ml protonated | Combination product | Combination seven - 35μg/s flux; high power/low power |
| e-liquid 9 and e-liquid 10e-liquid 9: 30/70 PG/VG ratio with nicotine concentration 4mg/ml protonated e-liquid 10: 70/30 PG/VG ratio with nicotine concentration 4mg/ml protonated | Combination product | Combination eight - 15μg/s flux; high PG(propylene glycol)/VG(vegetable glycerin) / low PG/VG |
Primary outcome
Subjective Effects - Strong Flavor (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Strong flavor will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled magnitude scale (gLMS) on a subjective scale (0-10, No sensation - Strongest Imaginable), with higher scores indicating a stronger perceived flavor.
Subjective Effects - Harshness/Irritancy (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Harshness/irritancy will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled magnitude scale (gLMS) on a subjective scale (0-10, No sensation - Strongest Imaginable), with higher scores indicating harsher/more irritating effects.
Subjective Effects - Throat Hit (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Throat hit will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled magnitude scale (gLMS) on a subjective scale (0-10, No sensation - Strongest Imaginable), with higher scores indicating a stronger throat hit.
Subjective Effects - Overall Like: Flavor (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Overall like: flavor will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled hedonic scale (LHS) on a subjective scale (0-10, most disliked - most liked), with higher scores indicating the flavor was liked more.
Subjective Effects - Overall Like: Harshness (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Overall like: harshness will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled hedonic scale (LHS) on a subjective scale (0-10, most disliked - most liked), with higher scores indicating the harshness was liked more.
Subjective Effects - Overall Like: Throat Hit (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Overall like: throat hit will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled hedonic scale (LHS) on a subjective scale (0-10, most disliked - most liked), with higher scores indicating the throat hit was liked more.
Subjective Effects - Overall Like: Warmth (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Overall like: warmth will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled hedonic scale (LHS) on a subjective scale (0-10, most disliked - most liked), with higher scores indicating the warmth was liked more.
Subjective Effects - Satisfying (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Satisfying will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating greater satisfaction.
Subjective Effects - Pleasant (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Pleasant will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating greater pleasantness.
Subjective Effects - Taste Good (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Taste good will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating better taste.
Subjective Effects - Calm (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Calm will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating feeling calmer.
Subjective Effects - Concentrate (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Concentrate will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating better ability to concentrate.
Subjective Effects - Awake (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Awake will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating feeling more awake/alert.
Subjective Effects - Reduce Hunger (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Reduce hunger will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating greater reduction in hunger.
Subjective Effects - Dizzy (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Dizzy will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating greater dizziness.
Subjective Effects - Feeling Sick (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Feeling sick will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating feeling more sick.
Subjective Effects - Want it Right Now (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Want it right now will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating a stronger immediate desire for the product.
Subjective Effects - Smell (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Smell will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating a stronger perceived smell. This item is drawn from the Electronic Cigarette Specific Effects Questionnaire, a modified/expanded version of the modified Cigarette Evaluation Questionnaire (mCEQ; Cappelleri et al., 2007) developed for ENDS. Participants rate the item on a 0-10 scale immediately following each bout. Item wording: 'Did the e-cig produce a smell?' (0 = not at all, 10 = extremely).
Subjective Effects - Visible Vapor (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Visible vapor will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating more visible vapor.
Subjective Effects - Importance Vapor (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Importance vapor will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating vapor visibility mattered more to the participant. This item is drawn from the Electronic Cigarette Specific Effects Questionnaire, a modified/expanded version of the modified Cigarette Evaluation Questionnaire (mCEQ; Cappelleri et al., 2007) developed for ENDS. Participants rate the item on a 0-10 scale immediately following each bout. Item wording: 'Is the vapor/cloud of the e-cig important to you?' (0 = not at all, 10 = extremely).
Subjective Effects - Puffs Similar (Combinations 1-5)
Time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.
Puffs similar will be assessed by the Electronic Cigarette Specific Effects questionnaire and consists of 1 item scored 0 - 10 with 0 being not at all and 10 being extremely, with higher scores indicating the puffs were perceived as more similar to the participant's usual product.
Smoking Urges - Brief Factor 1 (Intention/Desire)
Time frame: Assessed before and after the directed bout (Bout 1), and before, midway through, and after the ad libitum bout (Bout 2).
Brief Factor 1 (Intention/Desire) will be assessed by the Questionnaire of Smoking Urges-Brief (QSU-Brief; Tiffany \& Drobes, 1991; Toll et al., 2006). Factor 1 is the sum of 6 items, each rated on a 0-10 scale (0=strongly disagree, 10=strongly agree), yielding a total score range of 0-60, with higher scores indicating stronger urges.
Smoking Urges - Brief Factor 2 (Relief of Neg. Affect)
Time frame: Assessed before and after the directed bout (Bout 1), and before, midway through, and after the ad libitum bout (Bout 2).
Brief Factor 2 (Relief of Neg. Affect) will be assessed by the Questionnaire of Smoking Urges-Brief (QSU-Brief; Tiffany \& Drobes, 1991; Toll et al., 2006). Factor 2 is the sum of 4 items, each rated on a 0-10 scale (0=strongly disagree, 10=strongly agree), yielding a total score range of 0-40, with higher scores indicating stronger urges.
Withdrawal Symptoms - Minnesota Nicotine Withdrawal Scale (MNWS; Based on Hughes and Hatsukami, 1986)
Time frame: Assessed before and after the directed bout (Bout 1), and before, midway through, and after the ad libitum bout (Bout 2).
The Minnesota Nicotine Withdrawal Scale (MNWS; based on Hughes and Hatsukami, 1986 questionnaire) was measured using composite mean of MNWS items (irritability, anxiety, difficulty concentrating, restlessness, hunger/appetite, Impatient, depression, desire for sweets and craving) on a 0-10 scale (Not at all - Extremely), with higher scores indicating greater withdrawal severity.
11 secondary outcomes
Puff Duration
Time frame: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Number of Puffs
Time frame: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Puffing Time
Time frame: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Inter Puff Interval
Time frame: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Flow Rate
Time frame: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Mouth-level PM
Time frame: Will be measured after the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Mouth-level Nicotine
Time frame: Will be measured after the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Puff Duration - Combination 6,7 & 8
Time frame: Will be measured during the approximately 5-minute, 10-puff use bout
Sensory Feedback - Perceived Mouthful - Using Kangertech Subox Mini C (Sub-ohm Device)
Time frame: Will be measured during the approximately 5-minute, 10-puff use bout
Sensory Feedback - Perceived Draw Effort - Using Kangertech Subox Mini C (Sub-ohm Device)
Time frame: Will be measured during the approximately 5-minute, 10-puff use bout
Sensory Feedback - Throat Hit - Using Kangertech Subox Mini C (Sub-ohm Device)
Time frame: Will be measured during the approximately 5-minute, 10-puff use bout
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Sep 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 37733666El-Hellani A, Hanna E, Sharma M, Blohowiak R, Joseph P, Eid T, Nadim H, El-Hage R, Salman R, Karaoghlanian N, Adeniji A, Salam S, Talih F, Elbejjani M, Breland A, Eissenberg T, Shihadeh A, Baldassarri SR, Talih S. Nicotine flux as a powerful tool for regulating nicotine delivery from e-cigarettes: Protocol of two complimentary randomized crossover clinical trials. PLoS One. 2023 Sep 21;18(9):e0291786. doi: 10.1371/journal.pone.0291786. eCollection 2023.
- Individual participant dataSharing planned: No. Participants data will not be available to other researchers
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Soha Talih, PhD principal investigator
American University of Beirut Medical Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing e-liquid 1, e-liquid 2 and e-liquid 3 in people with Nicotine Vaping and Nicotine Dependence, run by American University of Beirut Medical Center at 1 site in Lebanon.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 18 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Lebanon. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 18 Sep 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Subjective Effects - Strong Flavor (Combinations 1-5) (time frame: Post Bout 1: assessed 5 minutes after onset of the directed 10-puff bout (average bout duration ~5 minutes). Post Bout 2: assessed 5 minutes after onset of the 60-minute ad libitum bout.). The study lists 24 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05430334, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Sep 2026.