Used as a reference standard in pharmaceutical research and quality control for the identification and quantification of 7-hydroxyquetiapine, a major active metabolite of quetiapine. It plays a critical role in metabolic studies, helping to understand the pharmacokinetics and biotransformation of quetiapine in human liver enzymes, particularly CYP3A4. Commonly employed in HPLC and LC-MS analytical methods to validate assay accuracy and sensitivity in biological matrices such as plasma, serum, or urine. Also utilized in drug development to assess metabolite contribution to overall therapeutic effect and safety profile.