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Phase I

Types of Studies for Healthy Volunteers

Clinical trials in Phase I are used to determine the safety, tolerability and pharmacokinetics (how your body absorbs, metabolizes and excretes) of a drug. From bioequivalence to single ascending dose studies, here’s what to know about the Phase I studies our clinics offer.

What happens in Phase I clinical trials?

Phase I studies are the first in a series of clinical trials in which a new drug or treatment is tested on a human subject. These tests help researchers determine the best dosing, timing and administration for a new treatment and also provide insights into how the drug reacts with the body. There are many types of studies that are conducted at our clinics. Sometimes, a study is a combination of multiple study types. These study types include:

Bioavailability (BA)

The rate and extent to which a drug is absorbed or is otherwise available to the treatment site in the body

Bioequivalence (BE)

Drugs with the same active ingredient(s) are compared at the same dosage under similar conditions

Drug-drug interaction

A modification of the effect of a drug when administered with another drug. Drugs with the same active ingredient(s) are compared at the same dosage under similar conditions

First in Human (FIH)

The first Phase I study in which the test product is administered to human beings. These usually have a small group dosed followed by a larger group after safety is assessed

Food effect (FE)

Assessing the effects of food on the rate of absorption of a drug when the drug product is administered shortly after a meal as compared to fasted conditions

Pharmacokinetic (PK)

Assessing the body’s absorption, distribution, metabolism and excretion of the drug. In other words, how your body affects the drug

Pharmacodynamics (PD)

Studies the biochemical and physiologic effects of the drug

  • Desired activity (main use of drug)
  • Undesirable effects
  • Therapeutic window
  • Duration of action of the drug on the body

Single ascending dose or multiple ascending dose (SAD/MAD)

SAD: In a SAD study, subjects are dosed in small groups. Each member of the group will receive either the drug or placebo. The first group will start with a very low dose and each following group will receive an escalated dose depending on the safety and tolerability of the drug. The dose escalation will stop once maximum tolerability and/or safety has been reached

MAD: In a MAD study, subjects receive multiple doses of the drug or placebo instead of just one


The QT interval is a measure of the time between the start of the Q wave and the end of the T wave in the heart’s electrical cycle. QT studies assess the drug’s effect on the QT interval under a strictly controlled environment. To analyze the effects, frequent electrocardiogram (ECG) recordings are collected to monitor QT changes AME (radiolabeled) – Madison clinic only 

These studies assess radioactivity levels through absorption, metabolism and excretion. Components are measured through collection of blood, fecal and urine samples

Get started today.

Fill out a brief form and we'll follow up to see if you qualify for a study. Or call us directly at 866-429-3700.