Publication / Source: Bioanalysis 2(03)
Authors: Dueker RS , Lohstroh NP, Giacomo AJ, Vuong TL, Keck DB, Vogel SJ
Accelerator mass spectrometry is now increasingly used in clinical studies with a microdose of 14C-labeled drug tracing a normal clinical dose (unlabeled); this has been termed ‘microtracing’ [11,12]. This high-sensitivity microtracing has been the only practical analytical solution for certain tissue- or fluid-limited analyses (cells, biopsies and pediatrics), when radiolysis or dosimetry issues are of concern, and for the study of low systemic bioavailability routes of delivery (transdermal, ocular and pulmonary) [13,14]. One microtracing design gaining wide industrial adoption is to measure human clearance and absolute bioavailability by the simultaneous dosing of an intravenous microdose of 14C-labeled drug with a clinical dose administered by an alternative intended route (e.g., oral) [5,12,15]. This suite of low-level tracer data can guide a future clinical-development program through dosage regimen design, formulation design and lifecycle management .