Used as a reference standard in pharmaceutical and biomedical research to study the metabolism of sulfamethoxazole, an antibiotic commonly prescribed for bacterial infections. It helps in identifying and quantifying metabolites in biological samples such as urine and plasma during drug metabolism studies. Widely applied in pharmacokinetic and toxicological analyses to understand the metabolic pathways and clearance mechanisms of sulfonamide drugs. Also utilized in analytical laboratories for calibration and validation of analytical methods like HPLC and mass spectrometry.