The study to be performed will define the rate of skin barrier recovery following micropatch application to the skin on the upper arm, volar forearm, and abdomen in healthy subjects.
Transdermal drug delivery (by way of patches that adhere to the skin and deliver drug in a time-dependent fashion) allows for systemic drug delivery through the skin, while avoiding many of the side effects and challenges associated with oral or intravenous drug delivery. One significant challenge limiting the number of drug compounds that can be transdermally delivered is the hydrophobic nature of the skin, which provides a barrier against absorption of drug molecules. Micropatches are a specialized type of patch that help drug molecules to cross the skin by creating micron-sized channels (also called micropores) in the skin, which makes the skin more permeable. Micropatches have been safely used in hundreds of patients for administration of drugs and vaccines through the skin. Studies have demonstrated that micropatch application is relatively painless and well-tolerated by most patients. Following micropatch application, the skin must reseal the micropores in order to restore the skin's full barrier function. In young healthy individuals this process takes approximately 48 to 72 hours when the skin is covered by an occlusive patch. The timeframe is longer in older individuals who are \>65 years of age. As evidenced by these age-related differences in restoration of skin barrier function, biological variation can have a significant effect on the skin's response after micropatch application. There are almost no data available regarding how race and ethnicity affect skin response to micropatch application. It is crucial to better understand how the rates of restoring barrier function vary in different racial/ethnic populations. This is very important for reducing potential for variability in drug delivery when new micropatches are developed in the future for treating diseases. In this study researchers are examining skin characteristics and response to micropatch application, but there will be no drugs delivered in this study. Hydration and color will be measured to characterize the epidermal properties of individuals of different self-identified race and ethnicity. Measurements of trans-epidermal water loss and electrical impedance will be used to evaluate the formation of micropores in the skin; the electrical impedance measurements will be used to calculate the rate of barrier function repair. All of these skin characteristics can be measured using noninvasive methods that are quick and painless.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
46
Each micropatch contains 50 tiny projections (800 um in length)
University of Iowa
Iowa City, Iowa, United States
Micropore Re-sealing Kinetics
The time required for the skin barrier to be restored after micropatch application at 3 sites on the body will be determined using electrical resistance measurements. Differences in the skin electrical resistance will be determined through measurements made every day with skin electrodes attached to an impedance meter. These data for micropore re-sealing are only collected from the micropatch sites.
Time frame: Four Days
Change in Trans-epidermal Water Loss
Percent change from baseline trans-epidermal water loss will be calculated after micropatch application at each body site, and these data are only collected from the micropatch sites. Percent change is calculated as (trans-epidermal water loss after micropatch application/baseline trans-epidermal water loss) x 100.
Time frame: Baseline (Day 0) and post micropatch application (Day 0)
Skin Color Groups
Lightness/darkness of the skin is measured with a tristimulus colorimeter and reported in a unitless value called L\*. Higher L\* values denote lighter skin, while lower L\* values denote darker skin. Data are calculated as the mean of measurements from all sites on the abdomen, and subjects are grouped into categories based on ranges of L\*.
Time frame: Baseline (Day 0)
Hydration
Baseline skin hydration will be measured using a capacitance probe. The software calculates arbitrary unitless values. Values less than 30 are considered very dry while values over 40 are considered sufficiently moisturized. Data are calculated as the mean of measurements from all 5 sites at each body location.
Time frame: Baseline (Day 0)
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