Racial/Ethnic Differences in Microneedle Response

Not Applicable

Completed

Conditions: Healthy

Interventions: Device: Microneedle patch

Registration Number: NCT03332628

Lead Sponsor: University of Iowa

Brief Summary: The study to be performed will define the rate of skin barrier recovery following microneedle treatment of the skin in healthy subjects of differing racial/ethnic backgrounds.

Detailed Description: 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 highly efficient barrier against the absorption of drug molecules. Microneedles are a minimally invasive means of allowing drug molecules to cross the skin by creating micron-sized channels (also called micropores) in the skin, thereby increasing its permeability. Microneedles have been safely used in hundreds of patients for administration of drugs and vaccines through the skin. Studies have demonstrated that microneedle treatment is relatively painless and well-tolerated by most patients.

Following microneedle treatment, the skin must heal the micropores in order to restore 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 for micropore closure is longer in elderly individuals (\>65 years of age), taking several days longer to restore the skin barrier. As evidenced by the differences in micropore closure rate observed with advancing age, biological variation can have a significant effect on the skin's healing properties. There are almost no data available regarding how race and ethnicity affect skin response to microneedle insertion. It is crucial to better understand how the rates of micropore closure vary in different racial/ethnic populations because the potential for variability in drug delivery is high if the recovery timeframes are poorly understood.

In this study we will measure hydration and color 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 micropore closure. All of these skin characteristics can be measured using noninvasive methods that are quick and painless.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 132

Inclusion Criteria

Subjects will be healthy men and women between 18 - 50 years of age who identify as African American or Black, Asian, Hispanic or Latino, American Indian/Alaska Native, Native Hawaiian/Other Pacific Islander, Caucasian/White, bi-/multiracial.

Exclusion Criteria

Unable to give consent
Severe general allergies requiring chronic treatment with steroids or antihistamines
Previous adverse reaction to microneedle insertion
Known allergy or adverse reaction to medical tape, adhesive, or aloe vera
Anyone with inflammatory diseases of the skin or diseases that alter immune function
Anyone taking any medications that impair the immune system will be excluded (contraceptives, vitamins, and topical products on the face will be allowed)
Anyone with current malignancy or history of malignancy present at the treatment site (upper arm)
Anyone with any of the following present at the treatment site (upper arm): eczema or scaling, inflammation, erythema, edema, blisters
Anyone with uncontrolled mental illness that would, in the opinion of the physician, affect their ability to understand or reliably participate in the study
Anyone taking medications in the following therapeutic classes will be excluded: HMGCoA reductase inhibitors ("statins"), oral or topical steroids, oral antibiotics, topical antibiotics at the local treatment site, topical antihistamines at the local treatment site, beta-blockers, and systemic or topical NSAIDS/analgesics
Anyone who is pregnant or nursing
Anyone with any condition that would, in the opinion of the PI or physician, place the subject at an unacceptable risk of injury or render the subject unable to meet the requirements of the protocol

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Microneedle application	Microneedle patch	This is the only study arm, which all participants complete. Nine sites on the upper arm will be identified. Baseline measurements of transepidermal water loss, electrical resistance, hydration, and color will be made at each site. The 9 sites will be divided into clusters of 3 sites each. The first cluster will have small microneedle patches applied to at each site. This will only occur on the first study day. Transepidermal water loss and electrical resistance are re-measured immediately after microneedle application. The sites will be covered with a small patch secured with medical tape. The second cluster of sites will not receive microneedle application but will just be covered with patches. The last cluster of sites will not have microneedle application or patches. Electrical resistance will be re-measured at all sites for 4 days after microneedle application. Measurements from the 2nd and 3rd cluster of sites allow each subject to serve as their own control in data analysis.

Primary Outcome Measures

Name	Time	Method
Micropore Closure Time	Five days	The time required for the skin barrier to be restored after microneedle application 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 closure are only collected from the microneedle sites. Using the data collected from all 5 days an average micropore closure time will be calculated, which can be compared between subsets of participants based on race/ethnicity.

Secondary Outcome Measures

Name	Time	Method
Change in Trans-epidermal Water Loss	Baseline (Day 0) and post microneedle application (Day 0)	Percent change from baseline trans-epidermal water loss will be calculated after microneedle application, and these data are only collected from the microneedle sites. Percent change is calculated as (trans-epidermal water loss after microneedle application/baseline trans-epidermal water loss) x 100.
Skin Color	Baseline (Day 0)	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 9 sites on the arm.
Hydration	Baseline (Day 0)	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 9 sites on the arm.