During Phase 1 studies, researchers generally test a new drug candidate in healthy volunteers. In most cases, 20 to 80 healthy volunteers participate in Phase 1.

The primary purpose of a Phase 1 study is to evaluate the safety of a new drug candidate before it proceeds to further clinical studies.  In addition to safety, we evaluate the bioavailabity of the drug through 2 factors

Rate & extent of release of drugs from its dosage form & its dissolution

Absorption of the drug into the systemic circulation