Which phase of pharmaceutical development involves small trials with fewer than 12 participants?

The phase of pharmaceutical development that involves small trials with fewer than 12 participants is Phase One. This phase is primarily focused on assessing the safety of a new drug or treatment, determining safe dosage ranges, and identifying side effects. It is often the first stage where the medication is introduced to human subjects, following extensive preclinical research.

During Phase One trials, researchers work with a small group, typically consisting of healthy volunteers or individuals with the condition being treated, to gather initial data on how the drug is metabolized and tolerated by the body. This stage is crucial for establishing a fundamental understanding of the drug's pharmacokinetics and pharmacodynamics before advancing to larger trials in later phases, which involve more participants and evaluate efficacy as well as safety.