From patient to tube: the importance of physiologically relevant quantitative bioanalytical assays

Circulating drug concentrations (clinical or preclinical) underly many interactions between industry and regulators; expressing safety coverage, pharmacokinetic-pharmacodynamic relationships or defining bioequivalence and dosing regimens. Accurate and precise measurement of these circulating concentrations is pivotal to the evolution and validation of any bioanalytical method that supports regulatory interactions. Since the bioanalyst is presented with a sub-aliquot of sampled biological matrix, how do they ensure this aliquot reflects the concentration in the subject at the time of collection? Here we share experiences from project support (internal and at CROs) that suggests we need to be ever vigilant translating the needs of bioanalysis with those of project teams. The simple mantra is for bioanalytical measurements to be physiologically relevant to the patient.