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Bioavailability Study of Oral Minoxidil 1 mg Tablet Compared with Topical Minoxidil Solution in Healthy Volunteers with Androgenetic Alopecia

Verified siteRegistered drugNo placebo

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What is this trial about?

A plain-language summary of the goals, design and what participants do

Androgenetic alopecia, a common form of hair loss that affects many adults, is being studied. The medication being tested is minoxidil, which can be taken as a 1 mg oral tablet or applied to the scalp as a 20 mg/ml skin solution.

The purpose of the study is to compare the amount of the drug that reaches the bloodstream when given in these two forms. This comparison, known as bioavailability, helps determine how effectively the medicine is absorbed. Participants will take a single dose of the tablet while fasting, have a short break, and then receive the skin solution under the same conditions. The study will also look at how the drug behaves after several doses taken over a short period.

All participants are healthy volunteers, and the trial follows a random order for the two treatments so that each person experiences both. Blood samples are taken to measure the drug levels, and the results will show which method provides higher exposure without causing unnecessary risk.

The research process

The trial runs in 10 steps – from screening to follow-up. Each step says what happens and what the team monitors.

Step 1
Enrollment and randomisation
After you join the study, you will be assigned to receive either the oral tablet first or the topical solution first. this assignment is called randomisation and ensures that the order of treatments is decided by chance.
Step 2
Fasting before each dosing period
Before every dose you must not eat or drink anything except water for at least ten hours. this condition is called fasting and helps to keep the measurement of the medicine consistent.
Step 3
Single dose oral administration
You will take one oral tablet that contains 1 mg of minoxidil with a small amount of water while you are fasting.
After the tablet is taken, a series of blood samples will be collected at several time points to measure how much medicine is in your bloodstream.
Step 4
Washout period after oral single dose
Following the single dose period, you will have a break of several days with no study medication. this break, called a washout period, allows the medicine to leave your body before the next treatment.
Step 5
Single dose topical administration
You will apply 2 ml of a topical solution containing minoxidil to the scalp while you are fasting.
Similar to the oral dose, a series of blood samples will be taken at defined times to assess the amount of medicine that reaches the bloodstream.
Step 6
Washout period after topical single dose
Another washout period will follow, during which no study medication is taken, to ensure the body is free of the previous dose before the next phase.
Step 7
Multiple dose oral administration
You will take the 1 mg oral tablet once each day while remaining fasting before each dose.
The tablets will be taken for enough days for the medicine level in your body to become stable, a condition known as steady state.
At the end of this period, additional blood samples will be collected to evaluate the steady‑state levels.
Step 8
Washout period after oral multiple dose
A further washout period will be observed after the multiple oral doses to clear the medicine before the next treatment.
Step 9
Multiple dose topical administration
You will apply 2 ml of the topical solution to the scalp each day, again fasting before each application.
The daily applications will continue until a steady state is reached, after which final blood samples will be taken.
Step 10
Final assessments and study completion
After all dosing periods are finished, a final set of measurements will be performed.
The study will then be concluded and no further study medication will be required.

Who can join the trial?

7 criteria

Women who, after receiving all study information, sign a written informed consent agreeing to take part
Age between 18 and 55 years
No major physical or mental health problems
No important abnormalities found in medical records or during the physical exam
No significant issues in blood tests (including haematology – blood cell counts, coagulation – clotting ability, biochemistry – chemical substances, and serology for hepatitis B, hepatitis C, and HIV) and urine tests
No major problems in vital signs (such as blood pressure and heart rate) and in the electrocardiogram (a test that records the heart’s electrical activity)
Women who could become pregnant must use a highly effective contraceptive method or remain abstinent while in the study

Who cannot join the trial?

13 criteria

Having any serious physical or mental (psychic) condition, especially if lab tests show abnormal liver or kidney markers such as GOT, GPT, GGT (enzymes that indicate liver health) higher than 2.5 times the normal limit, or total bilirubin (a substance the liver processes) higher than 1.5 times the normal limit.
Participating in another study that used experimental drugs within the past 3 months (or within at least 1 month or 5 half‑lives, whichever is longer, if the drug was already marketed).
Being unable to follow the study instructions or cooperate with the study procedures.
Having a history of difficulty swallowing.
Having scalp problems such as redness (erythema), dryness, or any other condition that could affect how the medication is absorbed.
Taking prescription medication in the last 15 days or not being off medication for at least 48 hours before receiving the study drug (women may continue using contraceptives, which must have been taken consistently for at least 4 weeks and not changed during the study).
Having a body mass index (BMI) outside the range of 18.5 to 30.0 (BMI is calculated as weight in kilograms divided by height in meters squared).
Having a known sensitivity or allergy to any medication.
Testing positive on a drug screen for cannabis, opiates, cocaine, or amphetamines.
Being a smoker.
Drinking alcohol every day or having experienced an acute alcohol overdose in the past week.
Having donated blood within the month before the study starts.
Being pregnant or breastfeeding.

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Verified sites

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Hospital Universitario De La Princesa
Verified
Madrid, Spain

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Investigated drugs

Minoxidil
is an oral tablet that participants take by mouth. In this study it is the test medication being evaluated to see how well it is absorbed into the body when taken on an empty stomach. The researchers are looking at how the drug behaves after a single dose and after several doses taken over time.
Regaxidil
is a topical solution that is applied to the skin. In the trial it serves as the comparator, meaning it is used to compare the absorption of the oral tablet against a form of the same medication that is normally used on the skin. This helps the investigators understand differences between taking the drug by mouth versus applying it to the skin.

Minoxidil

What is already known about the treatment

Minoxidil 1 mg tablet
This medication is taken orally as a small tablet swallowed with water. It is an approved drug that has been used for many years to treat hair loss and, in higher doses, high blood pressure. The main use in this trial is for androgenetic alopecia, a common form of pattern hair loss. It works by widening tiny blood vessels and opening potassium channels, which improves blood flow to hair follicles, and it is classified as a vasodilator and hair growth promoter.
Regaxidil 20 mg/ml solución cutánea
This product is a liquid solution that is applied directly to the scalp skin. It is an approved topical preparation for treating hair loss and is widely listed in medical literature. The primary indication is also androgenetic alopecia. It acts by dilating small blood vessels and opening potassium channels in the scalp, helping hair follicles receive more nutrients, and it belongs to the class of topical vasodilators and hair growth stimulants.

Investigated diseases

Androgenetic alopecia - It is a common type of hair loss that affects both men and women. The condition usually starts with thinning at the crown or front of the scalp and can spread over time. It is linked to genetic factors and the influence of male hormones on hair follicles, causing the follicles to become smaller and produce finer hairs. As the follicles shrink, they may eventually stop producing visible hair. The pattern and speed of hair loss differ from person to person.