Pharmacodynamics (PD) describes the biochemical and physiological effects of a medicinal drug after its administration. The dose–response relationship between pharmacokinetics and pharmacodynamic effects (e.g., linear vs. non-linear dose effects) plays a central role in understanding the specific characteristics of a drug and determining parameters such as therapeutic dose, therapeutic window, tolerability and safety.
The design of a pharmacodynamic study depends primarily on the mode of action and if a surrogate marker can be determined and quantified. The pharmacodynamic response of an insulin formulation is primarily measured using a euglycemic glucose clamp
examination, generally alongside pharmacokinetic assessments
. The glucose infusion rate (GIR) represents the surrogate marker of the respective insulin pharmacodynamics. The GIR profile provides endpoints such as the maximal glucose lowering effect (GIRmax), onset and duration of action and biological efficacy as determined by the total area under the GIR curve (AUC-GIR). Factors such as route of administration, drug concentration, volume of injectable drug, temperature and level of physical exercise can influence the distribution of a drug in the body over time and subsequently influence its pharmacodynamic response.