Effects of a Zinc Oxide Underarm Formula on Normal and Injured Skin in Healthy Volunteers

Study Overview
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Brief Summary
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Bothersome odor from the axilla is in most cases caused by Corynebacterium spp. Anti-microbial effects of zinc oxide (ZnO) are well documented. The overall objective of this study is to verify that repeated applications of a ZnO containing formulation can be directly linked to reduced growth of Corynebacterium spp. in the axillae.

Detailed Description
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In the trial the effects of the ZnO formulation on the skin of the forearms and axillae are investigated simultaneously. In both locations the skin is treated daily with the ZnO/placebo formulations. At day -8 skin areas of the forearms and the axillae are sampled by adhesive tape that is extracted in phosphate-buffered saline (PBS) and PBS extract analyzed on total proteins (BCA) and IL-1α. In the axillae swabs are taken for Corynebacterium spp. semi quantification and pH is measured in the axillae and on the forearm. At day 0 treated skin areas of the forearms and the axillae are sampled by adhesive tape that is extracted in PBS and PBS extract analyzed on total proteins (BCA) and IL-1α, and compared to adjacent non-treated skin. In the axillae and on the forearms, swabs are first taken for Corynebacterium spp. semi quantification followed by wounding using ablative fractional (10%) carbon dioxide laser at 20 millijoule/microbeam and pediatric lancet. pH is measured in the axillae and on the forearm. Progress of wound healing is assessed by dermatoscopy at days 3, 4 and 5. At day 5 swabs are taken in the axillae for Corynebacterium spp. semi quantification and pH is measured. Furthermore, skin areas of the axillae are sampled by adhesive tape that is extracted in PBS and PBS extract analyzed on total proteins (BCA) and IL-1α.

Official Title
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Effects of a Zinc Oxide Underarm Formula on Normal and Injured Skin: A Randomized and Double-blind Trial in Healthy Volunteers

Conditions
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Microbiome of the Axillae

Intervention / Treatment
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* Other: Formula with ZnO
* Other: Formula without ZnO


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy males and females Age between 18 and 65 years Non-smoking Written informed consent Exclusion Criteria: No current or past skin disorder Immunosuppressive treatment Pregnant and breast feeding women Hypersensitivity to zinc and/or other ingredients in the products

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: control<br>Formula without ZnO | Other: Formula without ZnO<br>* Forearms and axillae are treated by the volunteers once daily with a standardized amount of the roll-on without ZnO<br>|
| Active Comparator: intervention<br>Formula with ZnO | Other: Formula with ZnO<br>* Forearms and axillae are treated by the volunteers once daily with a standardized amount of the roll-on with ZnO<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Growth of Corynebacterium spp. after 8 days of treatment | Skin surface swabs are cultured, and Corynebacterium spp. identified by light microscopy/MALDI-TOF mass spectrometry and semiquantified. | Day 0 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Wound healing | Dermatoscopy is used to assess the erythema, crust formation and healing | Day 3, day 4 and day 5 | 
| Quantification of total proteins and interleukin (IL)-1α | Corneocytes are sampled on both forearms and axillae by adhesive tape (Sebutape®; CuDerm, Dallas, Texas, USA) for quantification of total proteins (BCA) and IL-1α levels by ELISA. | Day -8, day 0 and day 5 | 
| Changes in skin acidity level (pH) | pH measurements are performed on both axillae | Day -8 and day 5 | 
| Pain | McGill pain questionnaire | Day -8, day 0, day 3, day 4 and day 5 |