Nilotinib-d3 is primarily used in research and development as an internal standard in analytical chemistry, particularly in mass spectrometry. It aids in the accurate quantification and identification of nilotinib in biological samples, ensuring precision in pharmacokinetic studies. This deuterated compound is valuable in drug metabolism and bioavailability studies, helping researchers understand how nilotinib behaves in the body. Its application is critical in optimizing therapeutic drug monitoring and improving treatment strategies for chronic myeloid leukemia.