Zomepirac-d4 sodium salt is primarily used in research and analytical applications as an internal standard in mass spectrometry. Its deuterated structure allows for precise quantification and tracking of zomepirac and its metabolites in biological samples, ensuring accuracy in pharmacokinetic and metabolic studies. This compound is particularly valuable in drug development and forensic toxicology, where it aids in understanding drug behavior, metabolism, and elimination in the body. Its stability and isotopic labeling make it a reliable tool for high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) analyses.