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Completed

NCT Number: NCT05865431

Singlet Oxygen Quantification After Skin Exposure to Ultraviolet A (UVA) Light

The objective of this study is quantification of singlet oxygen species in the skin after exposure to Ultraviolet A (UVA) light

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Key information

Conditions

Sun Damaged Skin

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of California, Davis

Sacramento, California, 95819, United States

About this study

Ultraviolet (UV) radiation can lead to skin damage and cancer. Ultraviolet A (UVA) irradiation is 10 to 100 times more abundant in natural sunlight than ultraviolet B (UVB), thus human skin is exposed to more UVA irradiation daily.UVA irradiation is not completely filtered by clothing and it penetrates deeper into the dermis than UVB, potentially causing more damage. It is believed that skin cancer, photo aging, and skin immunomodulation are mediated by the reactive oxygen species (ROS) that are generated in response to UV radiation. Singlet oxygen (1O2) is one type of ROS. The aim of this study is to quantify the level of singlet oxygen generated in the skin after exposure to UVA radiation. Previous studies have used low dose ultraviolet A1(UVA1) irradiation of 20 J/cm2, which mimics exposure to strong sunlight of approximately two hours. This study will use UVA doses equivalent to or less than what humans are exposed to in daily life. Additionally, the aim is to quantify singlet oxygen produced in individuals of various skin types before and after application of sunscreens containing zinc oxide and avobenzone (sun protection factor 30). To our knowledge, there is no method for quantifying singlet oxygen in human skin after exposure to UVA light. This is a novel method that may help the investigators understand further the protective effects of various skin types, as well as sunscreens.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Subjects aged 18 years and older

Exclusion criteria

  • Those who are currently smoking or have smoked within the past 3 years.
  • Aspirin use
  • Multivitamins and supplements that contain vitamin E
  • Adults unable to consent
  • Individuals who are not yet adults (infants, children, teenagers)
  • Pregnant women
  • Prisoners

Treatment and study plan

Zinc Oxide and Avobenzone

Drug

Zinc Oxide is applied to one area of the forearm, Avobenzone is applied to another area of the forearm.

Primary outcomes

  1. Amount of singlet oxygen generated by the left forearm skin (2 cm^2) after exposure to UVA radiation dose of 0.33 J/cm2

    Time frame: 5 minutes at first visit

  2. Amount of singlet oxygen generated by the left forearm skin (2 cm^2) after exposure to UVA radiation dose of 8.25 J/cm2

    Time frame: 5 minutes at first visit

  3. Amount of singlet oxygen generated by the left forearm skin (2 cm^2) after exposure to UVA radiation dose of 16.5 J/cm2

    Time frame: 5 minutes at first visit

Secondary outcomes

  1. Difference in singlet oxygen (as measured by singlet oxygen molecule numbers) generated between individuals of different skin Fitzpatrick skin types

    Time frame: Within 24 hours

  2. Difference in singlet oxygen (as measured by thymidine dimer %) generated between individuals of different skin Fitzpatrick skin types

    Time frame: Within 24 hours

  3. Difference in singlet oxygen generation with avobenzone and zinc oxide sunscreens (sun protection factor 30 and 2mg/cm^2 applied for each) vs control (no sunscreen) after exposure to 444.1millijoules (mJ) /cm2 UVA exposure

    Time frame: Within 24 hours

    Difference in singlet oxygen generation (as measured by thymidine dimer %) with two different sunscreens (zinc oxide and avobenzone, each sun protection factor 30 and 2mg/cm^2 applied) vs control (no sunscreen) after exposure to 444.1mJ/cm2 UVA exposure

  4. Difference in singlet oxygen generation with avobenzone and zinc oxide sunscreens (sun protection factor 30 and 2mg/cm^2 applied for each) vs control (no sunscreen) after exposure to 444.1millijoules (mJ) /cm2 UVA exposure

    Time frame: Within 24 hours

    Difference in singlet oxygen generation (as measured by singlet oxygen molecule numbers) with two different sunscreens (zinc oxide and avobenzone, each sun protection factor 30 and 2mg/cm^2 applied) vs control (no sunscreen) after exposure to 444.1mJ/cm2 UVA exposure

  5. Change in appearance of skin pigmentation as measured by colorimetry after UVA exposure

    Time frame: Within 24 hours

Sponsors and collaborators

Lead sponsor

University of California, Davis

Other

Registry information

Important dates

Study start
2017
Primary completion
2018
Study completion
2018
First posted
May 18, 2023
Registry last updated
Apr 27, 2025

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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