Used as a stable isotope-labeled internal standard in mass spectrometry-based bioanalytical assays, particularly in pharmaceutical research and drug metabolism studies. Its deuterated structure allows for accurate quantification of piperazine-containing compounds by minimizing matrix effects and improving measurement precision. Commonly applied in pharmacokinetic and toxicokinetic studies where high sensitivity and specificity are required. Also utilized in metabolic stability assays to track and differentiate parent drugs from metabolites in biological matrices such as plasma, urine, and tissue homogenates.