Active, not recruitingNCT05929794Updated Jun 16, 2026

Pharmacokinetics of Transdermal Metronidazole

A Phase 4 interventional study of Metronidazole 0.75% Topical Gel and Metronidazole 0.75% Topical Cream in Healthy, sponsored by University of Iowa. Active, not recruiting at 1 site in United States. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-06-16.

Sponsored by University of Iowa · Phase 4, Interventional, and Basic science

Phase: Phase 4
Study type: Interventional
Enrollment: 24
Allocation: Non-randomized
Ages: 18 Years and older
Sex: All

Study summary

This is a crossover pharmacokinetic clinical study in healthy volunteers to compare metronidazole delivery through skin when a gel or cream metronidazole product is applied to skin treated with a micropatch.

Read the detailed description

The goal of this crossover pharmacokinetic clinical study in healthy volunteers is to compare metronidazole delivery through skin when a gel or cream metronidazole product is applied to skin treated with a micropatch. The main questions this study aims to answer are:

Is micropatch transdermal delivery dependent on the metronidazole product formulation?
Is transdermal delivery dependent on micropore lifetime of the skin after micropatch application?

Participants will be divided into groups based on metronidazole product (gel or cream).

The metronidazole product will be applied to micropatch-treated skin in study period one. Measurements of the skin barrier will be made before and after micropatch treatment.
Daily blood samples will be collected for up to 5 days after the micropatch and metronidazole are first applied.
Following a one-week washout period, the same study process will be repeated except that metronidazole product will be applied to skin without micropatch pretreatment.

Conditions studied

Healthy

Keywords

Microneedle
Micropatch
Transdermal
Metronidazole

In context

Lead sponsor

University of Iowa is the lead sponsor of 276 studies on the registry; 35 are open to participants now.

Of its 44 completed or terminated interventional studies of FDA-regulated products, 39 (89%) have results posted.

Counted across the registry records on this site, refreshed daily.

Who can participate

Ages eligible: 18 Years and older
Sexes eligible: All
Accepts healthy volunteers: Yes

Inclusion criteria

Men or non-pregnant women ≥18 years old, of any ethnic background
Provide written informed consent before initiation of any study procedures
Available for follow-up for the planned duration of the study
Able to communicate well with the investigators
Able to adhere to the study protocol schedule, study restrictions and examination schedule
Subjects deemed to be healthy, as determined by the study physician, based on medical history, current medical conditions, and medication history
Agrees not to participate in another clinical study during the study period unless the study is in the follow up phase and it has been 1 month since the subject received any experimental agents or treatments. The subject also agrees not to participate in an investigational drug study for at least 1 month after last procedure day
Agrees not to donate blood to a blood bank throughout participation in the study and for at least 2 months after last procedure day.

Exclusion criteria

Exclusion Criteria:

Unable to give consent
Inability to communicate or cooperate with the investigators
Known previous adverse reaction to microneedle insertion
Known allergy or adverse reaction to medical tape/adhesive, or aloe vera
Women who are pregnant or lactating
Abnormal vital signs or lab values deemed to be medically significant by the study physician or Principal Investigator
Positive urine drug screening test
Known prior serious adverse reaction or hypersensitivity to metronidazole or any metronidazole products
History of anaphylaxis to an antibiotic, antimicrobial, antifungal, antipartisitic, or antiviral drug
Current smoker or regular use of nicotine or tobacco products
Participation in any ongoing investigational drug trial or clinical drug trial unless the study is in the follow up phase and it has been ≥1 month since the subject received any experimental agents or treatments
Current use of medications in the following therapeutic classes: HMGCoA reductase inhibitors ("statins"), beta-blockers, oral or topical steroids, oral antibiotics, topical antibiotics at the local treatment site, topical antihistamines at the local treatment site, and oral or topical NSAIDs/analgesics. A subject who has recently used oral or topical steroids, antibiotics, antihistamines, or NSAIDs/analgesics may be enrolled if more than 5 elimination half-lives of the drug have passed since the last dose. The estimated elimination half-life for any specific drug will be obtained from standard pharmacy references such as Micromedex or other comparable references.
Current or recent use of any prescription medication that, in the opinion of the study physician or Principal Investigator, would present a safety risk when used concomitantly with metronidazole
Any current medical conditions (acute or chronic) that may pose a risk for study participation, as determined by the study physician or Principal Investigator
Any condition that would, in the opinion of the study physician or Principal Investigator, place the subject at an unacceptable risk of injury or render the subject unable to meet the requirements of the protocol
Uncontrolled mental illness that would, in the opinion of the study physician or Principal Investigator, affect the subject's ability to understand or reliably participate in the study
Subject has presence of a skin condition, excessive hair at the application site, sunburn, raised moles and scars, open sores at application site, scar tissue, tattoo, coloration, or any other local condition that would interfere with placement of patches, microneedles, study drug, skin assessment, or reactions to drug
Medical history of significant dermatologic diseases or conditions, such as atopy, psoriasis, vitiligo or conditions known to alter skin appearance or physiologic response (e.g. diabetes, porphyria).
Any current malignancy or history of malignancy at the treatment site
Prior history of keloids or excessive scarring
Prior history of skin pigmentation changes or significant dermal reaction to a topically applied drug product

Study design

Phase: Phase 4
Primary purpose: Basic science
Allocation: Non-randomized
Intervention model: Crossover assignment
Masking: None (open label)
Enrollment: 24 participants (estimated)

Study arms

Active comparator
Micropatch application + metronidazole 0.75% topical gel
Participants will have pre-treatment micropatch application followed by metronidazole 0.75% topical gel
Drug: Metronidazole 0.75% Topical Gel · Diagnostic Test: Transdermal water loss measurement · Diagnostic Test: Electrical Resistance · Diagnostic Test: Skin color measurement · Other: Micropatch application
Active comparator
Metronidazole 0.75% topical gel
Participants will have metronidazole 0.75% topical gel applied without the pre-treatment micropatch application
Drug: Metronidazole 0.75% Topical Gel · Diagnostic Test: Transdermal water loss measurement · Diagnostic Test: Electrical Resistance · Diagnostic Test: Skin color measurement
Active comparator
Micropatch application + metronidazole 0.75% topical cream
Participants will have pre-treatment micropatch application followed by metronidazole 0.75% topical cream
Drug: Metronidazole 0.75% Topical Cream · Diagnostic Test: Transdermal water loss measurement · Diagnostic Test: Electrical Resistance · Diagnostic Test: Skin color measurement · Other: Micropatch application
Active comparator
Metronidazole 0.75% topical cream
Participants will have metronidazole 0.75% topical cream applied without the pre-treatment micropatch application
Drug: Metronidazole 0.75% Topical Cream · Diagnostic Test: Transdermal water loss measurement · Diagnostic Test: Electrical Resistance · Diagnostic Test: Skin color measurement

Interventions

DrugMetronidazole 0.75% Topical Gel
Half of enrolled subjects will undergo this intervention. Baseline measurements of transepidermal water loss, electrical resistance, and color will be made at 3 sites on the upper arm. Color will only be measured at baseline. Micropatch application will occur at 2 sites, followed by application of metronidazole gel and then covered with an occlusive covering. One site will be covered with an occlusive covering only (no micropatch or gel). At 48 hours occlusive coverings and gel are removed and electrical resistance measurements are repeated. Fresh gel and occlusive patches are reapplied. At 96 hours the patches are removed and electrical resistance measurements repeated. Blood samples are taken daily for 5 days. Measurements from the 3rd site allow each subject to serve as their own control in data analysis. After a minimum 7 days washout period, all of these procedures will be repeated again except that there will be no micropatch application at any of the 3 sites.
DrugMetronidazole 0.75% Topical Cream
Half of enrolled subjects will undergo this intervention. Baseline measurements of transepidermal water loss, electrical resistance, and color will be made at 3 sites on the upper arm. Color will only be measured at baseline. Micropatch application will occur at 2 sites, followed by application of metronidazole cream and then covered with an occlusive covering. One site will be covered with an occlusive covering only (no micropatch or cream). At 48 hours occlusive coverings and cream are removed and electrical resistance measurements are repeated. Fresh cream and occlusive patches are reapplied. At 96 hours the patches are removed and electrical resistance measurements repeated. Blood samples are taken daily for 5 days. Measurements from the 3rd site allow each subject to serve as their own control in data analysis. After a minimum 7 days washout period, all of these procedures will be repeated again except that there will be no micropatch application at any of the 3 sites.
Diagnostic testTransdermal water loss measurement
Baseline measurements of transepidermal water loss will be made at 3 sites on the upper arm. In the study periods that have micropatch application, the measurements will be repeated after micropatch application and removal (before any metronidazole product is applied).
Diagnostic testElectrical Resistance
Baseline measurements of electrical resistance will be made at 3 sites on the upper arm. In the study periods that have micropatch application, the measurements will be repeated after micropatch application and removal (before any metronidazole product is applied). In all study periods the measurements will also be repeated at 48 hours and 96 hours, when metronidazole product and occlusive coverings are removed from the skin.
Diagnostic testSkin color measurement
Baseline measurements of skin color will be made at 3 sites on the upper arm.
OtherMicropatch application
All subjects will undergo this intervention. Baseline measurements of transepidermal water loss, electrical resistance, and color will be made at 3 sites on the upper arm (color only measured at baseline). Two sites will have micropatch application + metronidazole product with occlusive covering. One site will have micropatch application + occlusive covering, no metronidazole product. Micropatch application will only occur on day 1 (a micropatch is a patch of 50 microneedles). Transepidermal water loss and electrical resistance are repeated after micropatch application and removal. At 48 hours occlusive coverings and metronidazole are removed; electrical resistance measurements are repeated. Metronidazole product and fresh occlusive patches are reapplied. At 96 hours patches are removed and electrical resistance measurements repeated. Blood samples are taken daily for 5 days. Measurements from the 3rd site allow each subject to serve as their own control in data analysis.

What researchers measure

Primary outcomes

Measurement of maximum serum metronidazole concentration (Cmax)
Cmax is the highest metronidazole concentration measured in the serum.
Time frame: 0.5, 1, 1.5, 2, 4, 6, 8, 24, 48, 72, 96, 98, 100, 104, and 120 hours
Time of maximum serum metronidazole concentration (Tmax)
Tmax is the time point at which the maximum drug concentration in serum is measured.
Time frame: 0.5, 1, 1.5, 2, 4, 6, 8, 24, 48, 72, 96, 98, 100, 104, and 120 hours
Area under the serum-concentration curve from 0-120 hours
Area under the serum-concentration-time curve is a mathematical measure of total systemic exposure to metronidazole in the body.
Time frame: 0.5, 1, 1.5, 2, 4, 6, 8, 24, 48, 72, 96, 98, 100, 104, and 120 hours

Secondary outcomes

Skin color
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 collected as the mean of measurements from 3 sites on the upper arm.
Time frame: Baseline (Day 1)
Change in transepidermal water loss after micropatch application
The percent change in transepidermal water loss from baseline to post-micropatch application at the upper arm sites will be calculated. These data are only collected from the micropatch sites. Percent change is calculated as (transepidermal water loss after micropatch application/baseline transepidermal water loss) x 100. Data will be calculated as the mean of measurements from micropatch application sites at the upper arm.
Time frame: Baseline (Day 1) and post-micropatch application (Day 1)
Change in electrical resistance after micropatch application
The percent change in electrical resistance from baseline to post-micropatch application at the upper arm sites will be calculated. These data are only collected from the micropatch sites. Percent change is calculated as (electrical resistance after micropatch application/baseline electrical resistance) x 100. Data will be calculated as the mean of measurements from micropatch application sites at the upper arm.
Time frame: Baseline (Day 1) and post-micropatch application (Day 1)

Study locations

1 site

University of Iowa
Iowa City, Iowa 52242, United States

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

Updates

Tracking since Sep 25, 2026

No changes since tracking began. The registry record was last updated on Jun 16, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗

Registry details

Key details

Study ID: NCT05929794
Lead sponsor: University of Iowa
Responsible party: Nicole K Brogden (Associate Professor, University of Iowa) — Principal investigator
First posted: Jul 3, 2023
Start date: Feb 26, 2024
Primary completion: Jul 31, 2026 (estimated)
Completion: Dec 31, 2026 (estimated)
Last update: Jun 16, 2026

Oversight

Data monitoring committee: No
FDA-regulated drug: Yes
FDA-regulated device: No

View the source record on ClinicalTrials.gov ↗

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This study is active, not recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.

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