Ketorolac D4 is primarily used as an internal standard in analytical chemistry for the quantification of ketorolac in various samples. It is particularly valuable in mass spectrometry and chromatography techniques, where it helps ensure accurate and precise measurements by compensating for variations in sample preparation and instrument performance. This deuterated compound is essential in pharmacokinetic studies, allowing researchers to track the absorption, distribution, metabolism, and excretion of ketorolac in biological systems. Additionally, it plays a critical role in drug development and quality control processes, ensuring the reliability of data in clinical and forensic analyses.