Pigmentation From Visible Light Clinical Trial
Official title:
Effect of Vitamin E in the Prevention of Visible Light Induced Pigmentation
The main objective of the study is to assess the efficacy of an antioxidant in preventing
pigmentation induced by visible light in subjects with a phototype IV or V.
Patients will be exposed to a range of visible light to areas on the back to confirm study
eligibility. Patients showing pigmentation after 7 days on the exposed areas will be
eligible to continue.
Eligible patients will have study product applied to part of the back and placebo on another
part of the back. The placebo area will be exposed to the same range of light based as at
Day -7. The area where the antioxidant is applied will have a higher range of light exposure
than the area without the study product.
Seven days later, the areas will be examined to determine the lowest exposure inducing
pigmentation on the sides with placebo and with antioxidant. The color will also be measured
between two identical exposures with placebo and with antioxidant.
At Day -7, all subjects will be exposed to a pre-specified range of doses of visible light
on 6 areas of the back, each measuring 0.9 cm^2 in order to evaluate their pigmentary
response to visible light. The doses will be 20, 40, 80, 160, 320 and 640 J/cm^2. At Day 0,
a visual inspection will establish which subjects qualify for the remainder of the study,
based on the presence or absence of pigmentation induced by visible light. Subjects who do
not exhibit pigmentation at 640 J/cm^2 or lower will not pursue the study.
Subjects who demonstrate pigmentation will move on to the next step of the study. On this
same Day 0 visit, these subjects will be randomized to receive a topical antioxidant
preparation on one of two halves of their back and a control on the other side. The
antioxidant and control will be applied twice before the exposure to visible light is done
on Day 1: 24 hours prior (Day 0) and 30 minutes prior (Day 1) exposure. On Day 1, the skin
with antioxidant will be exposed to fluences of 80, 160, 320, 640, 1280 and 1920 J/cm^2
whereas that with control will be exposed to the same lower doses as on Day -7. This will be
done on a total of 12 different areas of 0.9 cm^2 each, with six on the side with
antioxidant preparation, and six on the side with control.
On Day 7±1, a visual assessment will be done of each exposed area, as well as quantitative
colorimetric measurements and a research photograph. The visual assessment will consist in
determination of the lowest fluence inducing visible pigmentation on each half back (with
antioxidant and with control). The colorimetric measurements will be done on areas exposed
to 320 and 640 J/cm^2 to compare the pigmentation present on skin to which antioxidant was
applied and on skin to which control was applied. The colorimetric assessment of adjacent
unexposed skin will also be performed. At Day 0, 1 and 7 visits, subjects will also be
evaluated for adverse events.
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Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Investigator, Outcomes Assessor), Primary Purpose: Prevention