Certified Clinical Research Coordinator (CCRC) Practice Exam

Which clinical phase of a study in humans is most likely characterized by an emphasis on pharmacokinetics and pharmacodynamics of a new investigational drug formulation?

1. Phase I

2. Phase II

3. Phase III

4. Phase IV

The correct answer is: Phase I

The first phase of clinical trials, often referred to as Phase I, is primarily aimed at assessing the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of a new investigational drug formulation in humans. During this phase, the study typically involves a small group of healthy volunteers or patients, where the focus is on understanding how the drug behaves in the body, including how it is absorbed, distributed, metabolized, and excreted. Pharmacokinetics refers to the movement of the drug through the body—how the body affects the drug, while pharmacodynamics refers to the effects the drug has on the body—how the drug interacts with its target once it reaches the site of action. This foundational knowledge gained in Phase I studies is critical for determining appropriate dosing, identifying potential side effects, and setting the stage for further evaluation of the drug's efficacy in later phases of clinical trials. Subsequent phases, such as Phase II and Phase III, while important in their own right for assessing efficacy and further safety, typically place more emphasis on how well the drug works in a larger patient population rather than the detailed pharmacokinetic and pharmacodynamic profiling. Phase IV, also known as post-marketing surveillance