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NCT Number: NCT06020248

Melanin and Dermal Uptake of Thirdhand Cigarette Smoke

This is a pilot study of the effects of dermal melanin on dermal uptake and retention of nicotine. The initial hypothesis is that higher levels of dermal melanin will correlate with lower uptake and longer retention of nicotine in the skin and body.

Recruiting

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Key information

Conditions

Age range

18 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Zuckerberg San Francisco General Hospital

San Francisco, California, 94110, United States

Location status: Recruiting

Location contact

Abel Huang

CONTACT

[email protected]

Suzyann Schick, PhD

PRINCIPAL_INVESTIGATOR

About this study

This is an interventional pharmacokinetic study comparing the uptake and metabolism of nicotine from smoke-exposed clothing in people with low high levels of dermal melanin and people with high levels of dermal melanin. The study will measure nicotine and metabolites of nicotine in the blood during exposure and in urine for 10 days after exposure.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adult nonsmoker
  • Aged 18-50
  • Skin reflectance scores below 150 or above 249 using the Mexameter 18 instrument
  • Healthy on the basis of medical history
  • Systolic blood pressure <150
  • Diastolic blood pressure <100
  • C-reactive protein <3.1 mg/ml
  • Liver function (AST and ALT) in normal ranges
  • kidney function (BUN) in normal ranges
  • LDL<131
  • Blood glucose <110
  • Not exposed to tobacco SHS.

Exclusion criteria

  • Dermal skin reflectance score between 150 and 249, as measured by the Mexameter 18 instrument.
  • Positive SARS-CoV-2 antibody test
  • Age 18 < or > 50
  • Physician diagnosis of asthma, heart disease, hypertension, thyroid disease, diabetes, renal or liver impairment or glaucoma.
  • Unstable psychiatric condition (such as current major depression, history of schizophrenia or bipolar disorder) or current use of more than two psychiatric medications
  • Systolic blood pressure greater than or equal to 150
  • Diastolic blood pressure greater than or equal to 100
  • Blood glucose greater than or equal to 110
  • LDL greater than or equal to130
  • Pregnancy or breastfeeding (by urine hCG and/or history)
  • Alcohol or illicit drug dependence within the past 5 years
  • BMI > 35 and < 18
  • Current illicit drug use (by history or urine test)
  • More than 1 pack year smoking history
  • Ever a daily marijuana smoker
  • Smoked anything within the last 3 months
  • Unable to hold allergy or other OTC medicines
  • Occupational exposure to smoke, dusts OR fumes
  • Concurrent participation in another clinical trial
  • Unable to communicate in English
  • No social security number

Treatment and study plan

Wear clothing that has been exposed to cigarette smoke for 3 hours.

Other

Cotton clothing is exposed to smoke from Marlboro Red (hard pack) cigarettes at 1-1.2 mg/m3 repeatedly, until total exposure equals 3 grams total particulate material. When tested after exposure, the clothing typically contained 59.15 +/- 18 µg nicotine and 42 +/- 24 ng NNK per gram. The mass of the clothing varies by size, but the average combination of pants and shirt contains 32 mgs nicotine and 23 µg NNK.

Primary outcomes

  1. Change in blood concentrations of nicotine

    Time frame: Baseline and 3 hours

    The study will measure concentration of nicotine in the blood before and after the dermal exposure to nicotine.

  2. Total combined urinary concentrations of the nicotine metabolites cotinine and 3-hydroxycotinine

    Time frame: First void, collected for 10 days

    The study will measure urinary metabolites of nicotine in the first void of the day for 10 days after exposure and sum the total mass of metabolites.

Secondary outcomes

  1. Urinary concentration of the NNK metabolite NNAL

    Time frame: First void, collected for 10 days

    The study will measure urinary metabolites of NNK in the first void of the day for 10 days after exposure and sum the total mass of metabolites.

Study contacts

Contact information is provided by the study sponsor or research team.

Abel Huang, BS

CONTACT

[email protected]

(415) 514-9011

Suzaynn F Schick, PhD

CONTACT

[email protected]

415-514-3535

Sponsors and collaborators

Lead sponsor

University of California, San Francisco

Other

Registry information

Acronym: THS05

Important dates

Study start
2023
Primary completion
2026
Study completion
2026
First posted
Aug 31, 2023
Registry last updated
Jun 16, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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