Quetiapine sulfoxide dihydrochloride is primarily used in the field of pharmaceutical research and development. It serves as a key intermediate or metabolite in the synthesis and study of quetiapine, an antipsychotic medication. Researchers utilize this compound to better understand the metabolic pathways and pharmacokinetics of quetiapine in the human body. It aids in the investigation of drug efficacy, safety, and potential side effects. Additionally, it plays a role in the development of analytical methods for detecting and quantifying quetiapine and its metabolites in biological samples, which is crucial for therapeutic drug monitoring and clinical studies.