Used primarily as a reference standard in pharmaceutical analysis and quality control. It serves as a metabolite marker in studies evaluating the metabolism and stability of ranitidine, a once widely used H2 receptor antagonist. Commonly employed in high-performance liquid chromatography (HPLC) and mass spectrometry (MS) to identify and quantify ranitidine degradation products in drug formulations and biological samples. Also utilized in research settings to understand oxidative metabolic pathways and to validate analytical methods for drug testing and pharmacokinetic studies.