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| ID | Type | Description | Link |
|---|---|---|---|
| 1R01DA052565-01A1 | U.S. NIH Grant/Contract | View source |
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| Name | Class |
|---|---|
| National Institutes of Health (NIH) | NIH |
| National Institute on Drug Abuse (NIDA) | NIH |
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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.
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 (16 and 32μg/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. In addition, 10 participants that completed the five use sessions will attend the lab for one additional visit with the aim of determining the influence of puff-by-puff variation of ENDS power and liquid composition on puffing behavior and sensory effects. During this visit participants will complete three directed puffing bouts (10 puffs). In each bout, participants will alternate puffs between two identical ENDS devices differing by a single design factor (combinations 6-8).
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Combination One - 16μg/s protonated nicotine flux | Experimental | The investigators will test the subjective effects of nicotine flux (16μg/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. |
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| Combination Two - 32μg/s protonated nicotine flux | Experimental | The investigators will test the subjective effects of nicotine flux (32μg/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. |
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| Combination Three - 16μg/s free base nicotine flux | Experimental | The investigators will test the subjective effects of nicotine flux (16μg/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. |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| e-liquid 1 | Combination Product | 30/70 PG/VG ratio with nicotine concentration 4mg/ml protonated |
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| Measure | Description | Time Frame |
|---|---|---|
| Subjective Measures of Nicotine Abstinence Symptoms - PROMIS-10 Global Health measures | The PROMIS-10 Global Health measures five domains: physical function, fatigue, pain, emotional distress, and social health. 10 Items are rated on a five-point scale (Poor=1, Fair=2, Good=3, Very good=4, Excellent=5) with higher scores indicating higher activity. | Visit 1 - Before starting the first session |
| Subjective Measures of Nicotine Abstinence Symptoms - The corresponding 4-item E-Cigarette Dependence | The corresponding 4-item E-Cigarette Dependence Scale that assesses dependence on ENDS. 4 Items are rated on a five-point scale (Never=1, Rarely=2, Sometimes=3, Often=4, Almost Always=5) with higher scores indicating higher activity. | Visit 1 - Before starting the first session |
| Subjective Measures of Nicotine Abstinence Symptoms - The corresponding 4-item Combustible cigarette Dependence | The corresponding 4-item Combustible cigarette Dependence Scale that assesses nicotine dependence for daily and nondaily smokers. 4 Items are rated on a five-point scale (Never=1, Rarely=2, Sometimes=3, Often=4, Always=5) with higher scores indicating higher activity. | Visit 1 - Before starting the first session |
| Nicotine Dependence questionnaires - The Fagerstrom Test of Nicotine Dependence | The Fagerstrom Test of Nicotine Dependence questionnaires that assesses nicotine dependence on ENDS. General questions not based on a scale. | Visit 1 - Before starting the first session |
| Subjective Measures of Nicotine Abstinence Symptoms - Product liking magnitude scale | Product liking will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled magnitude scale (gLMS) on a subjective scale (0-100, not at all - extremely), with higher scores indicating higher effects. |
| Measure | Description | Time Frame |
|---|---|---|
| Puff Duration | Measured topography Average Puff Duration (sec). | 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 (LPM). |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Soha Talih, PhD | American University of Beirut Medical Center | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| American University of Beirut | Beirut | 11-0236 | Lebanon |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 37733666 | Derived | 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. |
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Participants data will not be available to other researchers
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Each participant will attend the lab for five different visits that differ by nicotine flux and/or form in random order.
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Each participant will attend the lab for five different visits that differ by nicotine flux and/or form in random order. All sessions will be double-blind (Participant / Investigator). The analytical chemist will be providing the investigator with e-liquid in a random order in each session for each participant.
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| Combination Four - 32μg/s free base nicotine flux | Experimental | The investigators will test the subjective effects of nicotine flux (32μg/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. |
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| 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. |
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| Combination six - 0 ug/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. |
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| Combination seven - 32 ug/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 32 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. |
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| Combination seven - 16 ug/s flux; high PG/VG / low PG/VG | Experimental | The investigators will test the subjective effects (perceived mouthful, perceived draw effort, and throat hit) at two PG/VG 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. |
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| e-liquid 2 | Combination Product | 30/70 PG/VG ratio with nicotine concentration 10mg/ml protonated |
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| e-liquid 3 | Combination Product | 30/70 PG/VG ratio with nicotine concentration 4mg/ml free base |
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| e-liquid 4 | Combination Product | 30/70 PG/VG ratio with nicotine concentration 10mg/ml freebase |
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| e-liquid 5 | Combination Product | 30/70 PG/VG ratio with nicotine concentration 0mg/ml (placebo) |
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| e-liquid 6 | Combination Product | 30/70 PG/VG ratio with nicotine concentration 0mg/ml |
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| e-liquid 7 and e-liquid 8 | Combination 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 |
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| e-liquid 9 and e-liquid 10 | Combination 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 |
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| Up to 180 minutes |
| Subjective Measures of Nicotine Abstinence Symptoms - Product liking hedonic scale | Product liking will be assessed by the Electronic Cigarette Specific Effects questionnaire, general labeled hedonic scale (LHS) (0-100, most disliked sensation imaginable - most liked sensation imaginable), with higher scores indicating higher effects. | Up to 180 minutes |
| Subjective Measures of Nicotine Abstinence Symptoms - Drug Effect | The Drug Effect Questionnaire (DEQ) will measure acute effects consisting of seven items: drug strength, high, feeling stimulated, good effects, bad effects, wanting more drugs, and drug liking and this will be assessed on a subjective scale (0-100, not at all-extremely), with higher scores indicating higher effects. | Up to 180 minutes |
| Subjective Measures of Nicotine Abstinence Symptoms - Smoking urges | Smoking urges will be assessed by the smoking urges questionnaire on a subjective scale (0-100, Strongly disagree - strongly agree) with higher scores indicating higher urges. | Up to 180 minutes |
| Subjective Measures of Nicotine Abstinence Symptoms - Hughes and Hatsukami | The Hughes-Hatsukami Withdrawal Questionnaire (HHWQ) will be assessed by the Hughes and Hatsukami 1986 questionnaire on a subjective scale (0-100, Not at all - extremely). | Up to 180 minutes |
| Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout |
| Puff Interval | Measured topography Average Inter Puff Interval (sec). | 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). | Will be measured during the approximately 60-minute, ad lib use bout |
| Liquid consumed | Liquid consumption for each participant use session will be determined by pre- and post-weighing the ENDS device tank (g/session). | Will be measured after the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout |
| Carbonyl compound yield | Total Carbonyls Compounds will be quantified (microg/session). | Will be measured after the 60-minute, ad lib use bout |
| Nicotine flux | Nicotine flux will be quantified (mg/sec). | Will be measured after the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout |
| Sensory Feedback - Perceived Mouthful | 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. | Will be measured during the approximately 5-minute, 10-puff use bout |
| Sensory feedback - Perceived Draw Effort | 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. | Will be measured during the approximately 5-minute, 10-puff use bout |
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| Release Date | Unrelease Date | Unrelease Date Unknown | Reset Date | MCP Release Number |
|---|---|---|---|---|
| Jun 23, 2026 |
| ID | Term |
|---|---|
| D000072137 | Vaping |
| D014029 | Tobacco Use Disorder |
| ID | Term |
|---|---|
| D012907 | Smoking |
| D001519 | Behavior |
| D019966 | Substance-Related Disorders |
| D064419 | Chemically-Induced Disorders |
| D001523 | Mental Disorders |
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