Used primarily as a reference standard in pharmaceutical research and development, particularly in studies involving the metabolism and pharmacokinetics of aprepitant, a drug used to prevent nausea and vomiting. It serves as a metabolite marker in bioanalytical assays, helping to quantify drug breakdown in human plasma or other biological matrices. Its accurate detection supports the evaluation of drug efficacy and safety in clinical settings. Also employed in mass spectrometry and chromatography method validation to ensure reliable measurement of aprepitant and its related compounds.