Used primarily as a metabolite in pharmacological studies of thioridazine, a phenothiazine antipsychotic. Helps in understanding drug metabolism and clearance pathways in psychiatric medication research. Detected in biological samples to monitor patient compliance and assess metabolic activity during antipsychotic therapy. Also used in forensic toxicology to evaluate drug interactions and potential toxicity, especially related to cardiac side effects. Serves as a reference standard in analytical testing and chromatographic methods for accurate identification of thioridazine derivatives in clinical and research settings.