Used primarily as a stable isotope-labeled internal standard in mass spectrometry and pharmacokinetic studies. Enables accurate quantification of 1-aminoadamantane (memantine) and related compounds in biological matrices by providing a distinct mass signature with minimal interference. Commonly applied in drug metabolism research, bioanalytical assay development, and neuropharmacology studies where precise tracking of adamantane-based drugs is required. Its deuterated structure ensures high metabolic stability and detection specificity.