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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.
Full description
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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Inclusion criteria
Men or women 18 years of age or older at time of consent.
Subject, male or female, is willing to use effective contraceptive method for at least 30 days before Day -7 and at least until Day 7±1. Effective contraceptive methods are:
Capable of giving informed consent and the consent must be obtained prior to any study related procedures.
Skin phototype IV and V
Exhibits visible light-induced pigmentation at Day 0
Is willing to avoid exposure to UV radiation, including sunlight, phototherapy, or tanning salon, on the back for the duration of the study and 4 weeks preceding the study.
Exclusion criteria
Primary purpose
Allocation
Interventional model
Masking
10 participants in 2 patient groups
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Data sourced from clinicaltrials.gov
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