Synthesis of carbon-14-labelled peptides.

Carbon-14 (14 C)-labelled active pharmaceutical ingredients (APIs) and investigational medicinal products (IMPs) are required for phase 0/I to phase III mass balance and micro-dosing clinical trials. In some cases, this may involve the synthesis of 14 C-labelled peptides, and the analysis can be performed by accelerated mass spectrometry (AMS). The 14 C-peptide is typically prepared by the solid-phase peptide synthesis (SPPS) approach using custom-made glassware for the key coupling steps. Further modification of the purified 14 C-peptide can then be performed.