Primarily used in research and clinical settings as an isotopically labeled analog of temozolomide, this compound serves as an internal standard in mass spectrometry-based assays. It aids in the accurate quantification of temozolomide levels in biological samples, ensuring precision in pharmacokinetic and pharmacodynamic studies. Its application is critical in monitoring drug metabolism and distribution in patients undergoing chemotherapy, particularly for glioblastoma and other brain tumors. By providing a stable reference, it enhances the reliability of analytical methods, supporting the development and optimization of therapeutic protocols.