PK Sample Collection in Control Groups for GLP Studies

Rationale for Control Group PK Sampling

The American College of Toxicology and the National Institutes of Health recommend control group sampling in GLP studies to establish baseline measurements and ensure valid PK/PD modeling, which is essential for interpreting pharmacological effects and exposure-response relationships 1

Control group samples should be collected at the same timepoints as drug-treated groups to enable direct comparison and proper statistical analysis, as suggested by the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use 1
The National Institute of Standards and Technology recommends precise recording of sampling times using calendar time, which is essential for both control and treated groups 2, 3
The European Medicines Agency suggests including preinfusion samples to establish baseline levels before any intervention, which is particularly important when compounds may accumulate or when endogenous levels vary 4

The International Society on Thrombosis and Haemostasis recommends reporting all measurements, including those below the limit of quantification, rather than discarding them, as ignoring BLQ data may bias individual estimates 2
The Food and Drug Administration suggests ensuring control animals are matched in all relevant parameters to drug-treated groups to minimize confounding variability, which is critical for establishing baseline measurements and ensuring valid PK/PD modeling 1