Assess the Influence of Nicotine Flux and Nicotine Form on Subjective Effects Related to Dependency

NCT ID: NCT05430334

Last Updated: 2025-07-17

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

130 participants

Study Classification

INTERVENTIONAL

Study Start Date

2022-07-13

Study Completion Date

2025-07-11

Brief Summary

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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.

Detailed Description

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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).

Conditions

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Nicotine Vaping Nicotine Dependence Nicotine Addiction

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Each participant will attend the lab for five different visits that differ by nicotine flux and/or form in random order.
Primary Study Purpose

OTHER

Blinding Strategy

DOUBLE

Participants Investigators
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.

Study Groups

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Combination One - 16μg/s protonated nicotine flux

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.

Group Type EXPERIMENTAL

e-liquid 1

Intervention Type COMBINATION_PRODUCT

30/70 PG/VG ratio with nicotine concentration 4mg/ml protonated

Combination Two - 32μg/s protonated nicotine flux

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.

Group Type EXPERIMENTAL

e-liquid 2

Intervention Type COMBINATION_PRODUCT

30/70 PG/VG ratio with nicotine concentration 10mg/ml protonated

Combination Three - 16μg/s free base nicotine flux

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.

Group Type EXPERIMENTAL

e-liquid 3

Intervention Type COMBINATION_PRODUCT

30/70 PG/VG ratio with nicotine concentration 4mg/ml free base

Combination Four - 32μg/s free base nicotine flux

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.

Group Type EXPERIMENTAL

e-liquid 4

Intervention Type COMBINATION_PRODUCT

30/70 PG/VG ratio with nicotine concentration 10mg/ml freebase

Placebo - Combination Five - 0μg/s nicotine flux

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.

Group Type PLACEBO_COMPARATOR

e-liquid 5

Intervention Type COMBINATION_PRODUCT

30/70 PG/VG ratio with nicotine concentration 0mg/ml (placebo)

Combination six - 0 ug/s flux; high power/low power

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.

Group Type EXPERIMENTAL

e-liquid 6

Intervention Type COMBINATION_PRODUCT

30/70 PG/VG ratio with nicotine concentration 0mg/ml

Combination seven - 32 ug/s flux; high power/low power

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.

Group Type EXPERIMENTAL

e-liquid 7 and e-liquid 8

Intervention Type 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

Combination seven - 16 ug/s flux; high PG/VG / low PG/VG

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.

Group Type EXPERIMENTAL

e-liquid 9 and e-liquid 10

Intervention Type 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

Interventions

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e-liquid 1

30/70 PG/VG ratio with nicotine concentration 4mg/ml protonated

Intervention Type COMBINATION_PRODUCT

e-liquid 2

30/70 PG/VG ratio with nicotine concentration 10mg/ml protonated

Intervention Type COMBINATION_PRODUCT

e-liquid 3

30/70 PG/VG ratio with nicotine concentration 4mg/ml free base

Intervention Type COMBINATION_PRODUCT

e-liquid 4

30/70 PG/VG ratio with nicotine concentration 10mg/ml freebase

Intervention Type COMBINATION_PRODUCT

e-liquid 5

30/70 PG/VG ratio with nicotine concentration 0mg/ml (placebo)

Intervention Type COMBINATION_PRODUCT

e-liquid 6

30/70 PG/VG ratio with nicotine concentration 0mg/ml

Intervention Type COMBINATION_PRODUCT

e-liquid 7 and e-liquid 8

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

Intervention Type COMBINATION_PRODUCT

e-liquid 9 and e-liquid 10

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

Intervention Type COMBINATION_PRODUCT

Eligibility Criteria

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Inclusion Criteria

* 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

Exclusion Criteria

* 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
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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National Institutes of Health (NIH)

NIH

Sponsor Role collaborator

National Institute on Drug Abuse (NIDA)

NIH

Sponsor Role collaborator

American University of Beirut Medical Center

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Soha Talih, PhD

Role: PRINCIPAL_INVESTIGATOR

American University of Beirut Medical Center

Locations

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American University of Beirut

Beirut, , Lebanon

Site Status

Countries

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Lebanon

References

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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.

Reference Type DERIVED
PMID: 37733666 (View on PubMed)

Other Identifiers

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1R01DA052565-01A1

Identifier Type: NIH

Identifier Source: secondary_id

View Link

American University Of Beirut

Identifier Type: -

Identifier Source: org_study_id

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