Pharmacology
Pharmacodynamics (PD)
Definition
Pharmacodynamics is the study of the biochemical and physiological effects of a substance on the body and its mechanisms of action at the molecular, cellular, and organ system levels. While pharmacokinetics describes what the body does to a compound, pharmacodynamics describes what the compound does to the body. Key pharmacodynamic parameters include potency (EC50/IC50), efficacy (maximal effect), receptor binding affinity, and selectivity profile. In peptide research, understanding pharmacodynamics is essential for characterizing receptor interactions, defining dose-response relationships, and predicting functional outcomes in biological systems.