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.