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

July 15, 2025 updated by: American University of Beirut Medical Center

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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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 (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).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
130

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Soha Talih, PhD
  • Phone Number: 3627 +961-1-350000
  • Email: st38@aub.edu.lb

Study Locations

  • Lebanon
      • Beirut, Lebanon, 11-0236
        • American University of Beirut

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: 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.
Combination product: e-liquid 1
30/70 PG/VG ratio with nicotine concentration 4mg/ml protonated
Experimental: 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.
Combination product: e-liquid 2
30/70 PG/VG ratio with nicotine concentration 10mg/ml protonated
Experimental: 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.
Combination product: e-liquid 3
30/70 PG/VG ratio with nicotine concentration 4mg/ml free base
Experimental: 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.
Combination product: e-liquid 4
30/70 PG/VG ratio with nicotine concentration 10mg/ml freebase
Placebo Comparator: 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.
Combination product: e-liquid 5
30/70 PG/VG ratio with nicotine concentration 0mg/ml (placebo)
Experimental: 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.
Combination product: e-liquid 6
30/70 PG/VG ratio with nicotine concentration 0mg/ml
Experimental: 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.
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
Experimental: 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.
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

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Subjective Measures of Nicotine Abstinence Symptoms - PROMIS-10 Global Health measures
Time Frame: Visit 1 - Before starting the first session
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
Time Frame: Visit 1 - Before starting the first session
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
Time Frame: Visit 1 - Before starting the first session
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
Time Frame: Visit 1 - Before starting the first session
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
Time Frame: Up to 180 minutes
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.
Up to 180 minutes
Subjective Measures of Nicotine Abstinence Symptoms - Product liking hedonic scale
Time Frame: Up to 180 minutes
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
Time Frame: Up to 180 minutes
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
Time Frame: Up to 180 minutes
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
Time Frame: Up to 180 minutes
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

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Puff Duration
Time Frame: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
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
Time Frame: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Measured topography Average Flow rate (LPM).
Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
Puff Interval
Time Frame: Will be measured during the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
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
Time Frame: Will be measured during the approximately 60-minute, ad lib use bout
Measured topography Total Number of Puffs (puffs).
Will be measured during the approximately 60-minute, ad lib use bout
Liquid consumed
Time Frame: Will be measured after the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
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
Time Frame: Will be measured after the 60-minute, ad lib use bout
Total Carbonyls Compounds will be quantified (microg/session).
Will be measured after the 60-minute, ad lib use bout
Nicotine flux
Time Frame: Will be measured after the approximately 5-minute, 10-puff use bout and 60-minute, ad lib use bout
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
Time Frame: Will be measured during the approximately 5-minute, 10-puff use bout
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
Time Frame: Will be measured during the approximately 5-minute, 10-puff use bout
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

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
American University of Beirut Medical Center

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute on Drug Abuse (NIDA)
National Institutes of Health (NIH)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Soha Talih, PhD, American University of Beirut Medical center

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 13, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 11, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 11, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 8, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 20, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 24, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 17, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 15, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • American University Of Beirut
  • 1R01DA052565-01A1 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Participants data will not be available to other researchers

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

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