Used as a reference standard in pharmaceutical analysis for the detection and quantification of sulfamethoxazole metabolites in biological samples. Plays a role in studying drug metabolism, particularly in assessing the metabolic pathways of sulfonamide antibiotics. Commonly utilized in research settings to understand acetylation patterns in humans, which can influence drug efficacy and toxicity. Also employed in quality control during the development of analytical methods like HPLC and mass spectrometry for monitoring sulfonamide residues in environmental and clinical samples.