Assessment of Stability Extrapolation for Carbon‐14 Labelled Compounds for the Determination of Extended Retest Periods

Radiolabelled compound stability studies are an essential requirement to support human Absorption, Distribution, Metabolism and Excretion (hADME) clinical studies. This paper assesses the suitability of stability data extrapolation for carbon-14 labelled compounds following the principles set out in ICH Q1E guidelines. Data from seven stability studies at specific activities ranging from 8.2 to 81.0 μCi/mg have been assessed. Predictive models were employed to extrapolate stability data and determine extended retest periods, which were then subsequently verified against actual experimental results. In all cases, the predicted extended retest period aligned with the observed data. These findings demonstrate that stability extrapolations can be used to support extended retest periods for radiolabelled compounds.