Used primarily in research and development, it serves as a stable isotope-labeled internal standard in mass spectrometry for the accurate quantification of sulfadiazine and its metabolites in biological samples. This application is crucial in pharmacokinetic studies, helping to understand drug absorption, distribution, metabolism, and excretion in the body. Additionally, it aids in the development of analytical methods for quality control in pharmaceutical manufacturing, ensuring the consistency and safety of sulfadiazine-based medications. Its use in environmental studies also helps monitor the presence and degradation of sulfadiazine in ecosystems, contributing to environmental safety assessments.