N-Butyldeoxynojirimycin hydrochloride (NB-DNJ HCl, CAS 210110-90-0) is a synthetic iminosugar derivative, specifically an N-alkylated analog of deoxynojirimycin. It functions as a potent and competitive inhibitor of α-glucosidase I and II, key enzymes involved in the N-linked glycosylation pathway within the endoplasmic reticulum. Its primary application is as an investigational drug for the treatment of type 1 Gaucher disease, a lysosomal storage disorder. By inhibiting glucosylceramide synthase, it reduces the substrate accumulation in cells. It has also been studied for its potential antiviral effects, particularly against viruses like HIV and hepatitis B, which utilize host cell glycosylation machinery. The compound is typically used in biochemical research to study glycosylation processes and as a reference standard.