Tosedostat-d5 is primarily used in research and development within the field of oncology. It serves as a deuterated analog of Tosedostat, a compound known for its inhibitory effects on aminopeptidases, which are enzymes involved in protein metabolism and cancer cell survival. The deuterated form is often employed in pharmacokinetic and metabolic studies to track the behavior and distribution of the parent compound in biological systems. Its use helps researchers understand the drug's absorption, distribution, metabolism, and excretion (ADME) properties more precisely, aiding in the optimization of therapeutic strategies for cancer treatment. Additionally, Tosedostat-d5 is utilized in mass spectrometry and other analytical techniques as an internal standard to ensure accurate quantification of Tosedostat in complex biological matrices. This contributes to the development of more effective and targeted cancer therapies.