Notes: Butyryl norfentanyl (hydrochloride) (Item No. 19428) is an analytical reference material that is structurally categorized as an opioid. It is a presumptive metabolite of butyryl fentanyl (Item Nos. 14728 / 19734). The physiological and toxicological properties of this compound are not known. This product is intended for research and forensic applications.