Used primarily as an impurity reference standard in pharmaceutical quality control and analytical testing of felodipine formulations. It helps in identifying degradation products and ensuring the stability and purity of felodipine in drug products. Commonly employed in HPLC and mass spectrometry methods for accurate quantification and detection of related substances in bulk drugs and tablets. Also useful in pharmacokinetic and metabolic studies to understand the breakdown pathways of calcium channel blockers in biological systems.